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Ferroelectricity

Ferroelectricity is a characteristic of certain materials that have a spontaneous electric polarization that can be reversed by the application of an external electric field. All ferroelectrics are also piezoelectric and pyroelectric, with the additional property that their natural electrical polarization is reversible. The term is used in analogy to ferromagnetism, in which a material exhibits a permanent magnetic moment. Ferromagnetism was already known when ferroelectricity was discovered in 1920 in Rochelle salt by Joseph Valasek. Thus, the prefix ferro, meaning iron, was used to describe the property despite the fact that most ferroelectric materials do not contain iron. Materials that are both ferroelectric and ferromagnetic are known as multiferroics.

Polarization
When most materials are electrically polarized, the polarization induced, P, is almost exactly proportional to the applied external electric field E; so the polarization is a linear function. This is called linear dielectric polarization (see figure). Some materials, known as paraelectric materials, show a more enhanced nonlinear polarization (see figure). The electric permittivity, corresponding to the slope of the polarization curve, is not constant as in linear dielectrics but is a function of the external electric field.

In addition to being nonlinear, ferroelectric materials demonstrate a spontaneous nonzero polarization (after entrainment, see figure) even when the applied field E is zero. The distinguishing feature of ferroelectrics is that the spontaneous polarization can be reversed by a suitably strong applied electric field in the opposite direction; the polarization is therefore dependent not only on the current electric field but also on its history, yielding a hysteresis loop. They are called ferroelectrics by analogy to ferromagnetic materials, which have spontaneous magnetization and exhibit similar hysteresis loops.

Typically, materials demonstrate ferroelectricity only below a certain phase transition temperature, called the Curie temperature (TC) and are paraelectric above this temperature: the spontaneous polarization vanishes, and the ferroelectric crystal transforms into the paraelectric state. Many ferroelectrics lose their pyroelectric properties above TC completely, because their paraelectric phase has a centrosymmetric crystal structure.

Applications
The nonlinear nature of ferroelectric materials can be used to make capacitors with adjustable capacitance. Typically, a ferroelectric capacitor simply consists of a pair of electrodes sandwiching a layer of ferroelectric material. The permittivity of ferroelectrics is not only adjustable but commonly also very high, especially when close to the phase transition temperature. Because of this, ferroelectric capacitors are small in physical size compared to dielectric (non-tunable) capacitors of similar capacitance.

The spontaneous polarization of ferroelectric materials implies a hysteresis effect which can be used as a memory function, and ferroelectric capacitors are indeed used to make ferroelectric RAM for computers and RFID cards. In these applications thin films of ferroelectric materials are typically used, as this allows the field required to switch the polarization to be achieved with a moderate voltage. However, when using thin films a great deal of attention needs to be paid to the interfaces, electrodes and sample quality for devices to work reliably.

Ferroelectric materials are required by symmetry considerations to be also piezoelectric and pyroelectric. The combined properties of memory, piezoelectricity, and pyroelectricity make ferroelectric capacitors very useful, e.g. for sensor applications. Ferroelectric capacitors are used in medical ultrasound machines (the capacitors generate and then listen for the ultrasound ping used to image the internal organs of a body), high quality infrared cameras (the infrared image is projected onto a two dimensional array of ferroelectric capacitors capable of detecting temperature differences as small as millionths of a degree Celsius), fire sensors, sonar, vibration sensors, and even fuel injectors on diesel engines.

Another idea of recent interest is the ferroelectric tunnel junction (FTJ) in which a contact is made up by nanometer-thick ferroelectric film placed between metal electrodes. The thickness of the ferroelectric layer is small enough to allow tunneling of electrons. The piezoelectric and interface effects as well as the depolarization field may lead to a giant electroresistance (GER) switching effect.

Yet another burgeoning application is multiferroics, where researchers are looking for ways to couple magnetic and ferroelectric ordering within a material or heterostructure; there are several recent reviews on this topic.

Catalytic properties of ferroelectrics have been studied since 1952 when Parravano observed anomalies in CO oxidation rates over ferroelectric sodium and potassium niobates near the Curie temperature of these materials. Surface-perpendicular component of the ferroelectric polarization can dope polarization-dependent charges on surfaces of ferroelectric materials, changing their chemistry. This opens the possibility of performing catalysis beyond the limits of the Sabatier principle. Sabatier principle states that the surface-adsorbates interaction has to be an optimal amount: not too weak to be inert toward the reactants and not too strong to poison the surface and avoid desorption of the products: a compromise situation. This set of optimum interactions is usually referred to as "top of the volcano" in activity volcano plots. On the other hand, ferroelectric polarization-dependent chemistry can offer the possibility of switching the surface—adsorbates interaction from strong adsorption to strong desorption, thus a compromise between desorption and adsorption is no longer needed. Ferroelectric polarization can also act as an energy harvester. Polarization can help the separation of photo-generated electron-hole pairs, leading to enhanced photocatalysis. Also, due to pyroelectric and piezoelectric effects under varying temperature (heating/cooling cycles) or varying strain (vibrations) conditions extra charges can appear on the surface and drive various (electro)chemical reactions forward.

Photoferroelectric imaging is a technique to record optical information on pieces of ferroelectric material. The images are nonvolatile and selectively erasable.

Materials
The internal electric dipoles of a ferroelectric material are coupled to the material lattice so anything that changes the lattice will change the strength of the dipoles (in other words, a change in the spontaneous polarization). The change in the spontaneous polarization results in a change in the surface charge. This can cause current flow in the case of a ferroelectric capacitor even without the presence of an external voltage across the capacitor. Two stimuli that will change the lattice dimensions of a material are force and temperature. The generation of a surface charge in response to the application of an external stress to a material is called piezoelectricity. A change in the spontaneous polarization of a material in response to a change in temperature is called pyroelectricity.

Generally, there are 230 space groups among which 32 crystalline classes can be found in crystals. There are 21 non-centrosymmetric classes, within which 20 are piezoelectric. Among the piezoelectric classes, 10 have a spontaneous electric polarization which varies with temperature; thus they are pyroelectric. Ferroelectricity is a subset of pyroelectricity, which brings spontaneous electronic polarization to the material.

Ferroelectric phase transitions are often characterized as either displacive (such as BaTiO3) or order-disorder (such as NaNO2), though often phase transitions will demonstrate elements of both behaviors. In barium titanate, a typical ferroelectric of the displacive type, the transition can be understood in terms of a polarization catastrophe, in which, if an ion is displaced from equilibrium slightly, the force from the local electric fields due to the ions in the crystal increases faster than the elastic-restoring forces. This leads to an asymmetrical shift in the equilibrium ion positions and hence to a permanent dipole moment. The ionic displacement in barium titanate concerns the relative position of the titanium ion within the oxygen octahedral cage. In lead titanate, another key ferroelectric material, although the structure is rather similar to barium titanate the driving force for ferroelectricity is more complex with interactions between the lead and oxygen ions also playing an important role. In an order-disorder ferroelectric, there is a dipole moment in each unit cell, but at high temperatures they are pointing in random directions. Upon lowering the temperature and going through the phase transition, the dipoles order, all pointing in the same direction within a domain.

An important ferroelectric material for applications is lead zirconate titanate (PZT), which is part of the solid solution formed between ferroelectric lead titanate and anti-ferroelectric lead zirconate. Different compositions are used for different applications; for memory applications, PZT closer in composition to lead titanate is preferred, whereas piezoelectric applications make use of the diverging piezoelectric coefficients associated with the morphotropic phase boundary that is found close to the 50/50 composition.

Ferroelectric crystals often show several transition temperatures and domain structure hysteresis, much as do ferromagnetic crystals. The nature of the phase transition in some ferroelectric crystals is still not well understood.

In 1974 R.B. Meyer used symmetry arguments to predict ferroelectric liquid crystals, and the prediction could immediately be verified by several observations of behavior connected to ferroelectricity in smectic liquid-crystal phases that are chiral and tilted. The technology allows the building of flat-screen monitors. Mass production between 1994 and 1999 was carried out by Canon. Ferroelectric liquid crystals are used in production of reflective LCoS.

In 2010 David Field found that prosaic films of chemicals such as nitrous oxide or propane exhibited ferroelectric properties. This new class of ferroelectric materials exhibit "spontelectric" properties, and may have wide-ranging applications in device and nano-technology and also influence the electrical nature of dust in the interstellar medium.

Other ferroelectric materials used include triglycine sulfate, polyvinylidene fluoride (PVDF) and lithium tantalate. A single atom thick ferroelectric monolayer can be created using pure bismuth.

It should be possible to produce materials which combine both ferroelectric and metallic properties simultaneously, at room temperature. According to research published in 2018 in Nature Communications, scientists were able to produce a two-dimensional sheet of material which was both ferroelectric (had a polar crystal structure) and which conducted electricity.

Theory
An introduction to Landau theory can be found here. Based on Ginzburg–Landau theory, the free energy of a ferroelectric material, in the absence of an electric field and applied stress may be written as a Taylor expansion in terms of the order parameter, P. If a sixth order expansion is used (i.e. 8th order and higher terms truncated), the free energy is given by:

\begin{array} {ll} \Delta E= & \frac{1}{2}\alpha_0\left(T-T_0\right)\left(P_x^2+P_y^2+P_z^2\right)+ \frac{1}{4}\alpha_{11}\left(P_x^4+P_y^4+P_z^4\right)\\ & +\frac{1}{2}\alpha_{12}\left(P_x^2 P_y^2+P_y^2 P_z^2+P_z^2P_x^2\right)\\ & +\frac{1}{6}\alpha_{111}\left(P_x^6+P_y^6+P_z^6\right)\\ & +\frac{1}{2}\alpha_{112}\left[P_x^4\left(P_y^2+P_z^2\right) +P_y^4\left(P_x^2+P_z^2\right)+P_z^4\left(P_x^2+P_y^2\right)\right]\\ & +\frac{1}{2}\alpha_{123}P_x^2P_y^2P_z^2 \end{array} $$

where Px, Py, and Pz are the components of the polarization vector in the x, y, and z directions respectively, and the coefficients, $$\alpha_i, \alpha_{ij}, \alpha_{ijk}$$ must be consistent with the crystal symmetry. To investigate domain formation and other phenomena in ferroelectrics, these equations are often used in the context of a phase field model. Typically, this involves adding a gradient term, an electrostatic term and an elastic term to the free energy. The equations are then discretized onto a grid using the finite difference method or finite element method and solved subject to the constraints of Gauss's law and Linear elasticity.

In all known ferroelectrics, $$\alpha_0 > 0$$ and $$\alpha_{111} > 0$$. These coefficients may be obtained experimentally or from ab-initio simulations. For ferroelectrics with a first order phase transition, $$\alpha_{11} < 0$$, whereas $$\alpha_{11} > 0$$ for a second order phase transition.

The spontaneous polarization, Ps of a ferroelectric for a cubic to tetragonal phase transition may be obtained by considering the 1D expression of the free energy which is:

\Delta E=\frac{1}{2}\alpha_0\left(T-T_0\right)P_x^2+\frac{1}{4}\alpha_{11}P_x^4+\frac{1}{6}\alpha_{111}P_x^6 $$

This free energy has the shape of a double well potential with two free energy minima at $$P_x = P_s$$, the spontaneous polarization. We find the derivative of the free energy, and set it equal to zero in order to solve for $$P_s$$:

\frac{\partial \Delta E}{\partial P_x}=\alpha_0\left(T-T_0\right)P_x+\alpha_{11}P_x^3+\alpha_{111}P_x^5 $$

0=\frac{\partial \Delta E}{\partial P_x}=P_s \left[ \alpha_0\left(T-T_0\right)+\alpha_{11}P_s^2+\alpha_{111}P_s^4\right] $$

Since the Ps = 0 solution of this equation rather corresponds to a free energy maxima in the ferroelectric phase, the desired solutions for Ps correspond to setting the remaining factor to zero:

\alpha_0\left(T-T_0\right)+\alpha_{11}P_s^2+\alpha_{111}P_s^4=0 $$

whose solution is:

 * $$P_s^2=\frac{1}{2\alpha_{111}}\left[-\alpha_{11}\pm\sqrt{\alpha_{11}^2+4\alpha_0\alpha_{111}\left(T_0-T\right)} \;\right]$$

and eliminating solutions which take the square root of a negative number (for either the first or second order phase transitions) gives:

 * $$P_s= \pm \sqrt{\frac{1}{2\alpha_{111}}\left[-\alpha_{11}+\sqrt{\alpha_{11}^2+4\alpha_0\alpha_{111}\left(T_0-T\right)} \;\right]}$$

If $$\alpha_{11}=0$$, the solution for the spontaneous polarization reduces to:

 * $$P_s= \pm\sqrt[4]{\frac{\alpha_0\left(T_0-T\right)}{\alpha_{111}}}$$

The hysteresis loop (Px versus Ex) may be obtained from the free energy expansion by including the term -Ex Px corresponding to the energy due to an external electric field Ex interacting with the polarization Px, as follows:

\Delta E=\frac{1}{2}\alpha_0\left(T-T_0\right)P_x^2+\frac{1}{4}\alpha_{11}P_x^4+\frac{1}{6}\alpha_{111}P_x^6 - E_x P_x $$

We find the stable polarization values of Px under the influence of the external field, now denoted as Pe, again by setting the derivative of the energy with respect to Px to zero:

\frac{\partial \Delta E}{\partial P_x}=\alpha_0\left(T-T_0\right)P_x+\alpha_{11}P_x^3+\alpha_{111}P_x^5 - E_x = 0 $$

E_x=\alpha_0\left(T-T_0\right)P_e+\alpha_{11}P_e^3+\alpha_{111}P_e^5 $$

Plotting Ex (on the X axis) as a function of Pe (but on the Y axis) gives an S-shaped curve which is multi-valued in Pe for some values of Ex. The central part of the 'S' corresponds to a free energy local maximum (since $$\frac{\partial^2 \Delta E}{\partial P_x^2}<0$$ ). Elimination of this region, and connection of the top and bottom portions of the 'S' curve by vertical lines at the discontinuities gives the hysteresis loop of internal polarization due to an external electric field.

Sliding ferroelectricity
Sliding ferroelectricity is widely found but only in two-dimensional (2D) van der Waals stacked layers. The vertical electric polarization is switched by in-plane interlayer sliding.

title: Ferroelectricity


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Thomas Kyd

Thomas Kyd (baptised 6 November 1558; buried 15 August 1594) was an English playwright, the author of The Spanish Tragedy, and one of the most important figures in the development of Elizabethan drama.

Although well known in his own time, Kyd fell into obscurity until 1773 when Thomas Hawkins, an early editor of The Spanish Tragedy, discovered that Thomas Heywood, in his Apologie for Actors (1612), attributed the play to Kyd. A hundred years later, scholars in Germany and England began to shed light on his life and work, including the controversial finding that he may have been the author of a Hamlet play pre-dating Shakespeare's, which is now known as the Ur-Hamlet.

Early life
Thomas Kyd was the son of Francis and Anna Kyd. There are no records of the day he was born, but he was baptised in the church of St Mary Woolnoth in the Ward of Langborn, Lombard Street, London on 6 November 1558. The baptismal register at St Mary Woolnoth carries this entry: "Thomas, son of Francis Kydd, Citizen and Writer of the Courte Letter of London". Francis Kydd was a scrivener and in 1580 was warden of the Scriveners' Company.

In October 1565 the young Kyd was enrolled in the newly founded Merchant Taylors' School, whose headmaster was Richard Mulcaster. Fellow students included Edmund Spenser and Thomas Lodge. Here, Kyd received a well-rounded education, with the curriculum including Italian, Latin, Greek, music, drama, physical education, and "good manners". There is no evidence that Kyd went on to university. He may have followed in his father's professional footsteps because there are two letters written by him where his handwriting style is similar to that of a scrivener.

Career

Evidence suggests that in the 1580s Kyd became an important playwright, but little is known about his activity. Francis Meres placed him among "our best for tragedy" and Heywood elsewhere called him "Famous Kyd". Ben Jonson mentions him in the same breath as Christopher Marlowe (with whom, in London, Kyd at one time shared a room) and John Lyly in the Shakespeare First Folio.

The Spanish Tragedy was probably written in the mid to late 1580s, with its first recorded performance on 23 February 1592 by Lord Strange's Men. The earliest surviving edition was printed in 1592, the full title being The Spanish Tragedie, Containing the lamentable end of Don Horatio, and Bel-imperia: with the pittifull death of olde Hieronimo. However, the play was usually known simply as "Hieronimo" after the protagonist. It was arguably the most popular play of the "Age of Shakespeare" and set new standards in effective plot construction and character development. There were "twenty-nine performances between 1592 and 1597" and "eleven editions between 1592 and 1633", which the historian J. R. Mulryne states is "a tally unequaled by any of the plays of Shakespeare”. In 1602 a version of the play with "additions" was published. Philip Henslowe's diary records payment to Ben Jonson for additions that year, but it is disputed whether the published additions reflect Jonson's work or if they were actually composed for a 1597 revival of The Spanish Tragedy also mentioned by Henslowe.

Other works by Kyd are his translations of Torquato Tasso's Padre di Famiglia, published as The Householder's Philosophy (1588), and of Robert Garnier's Cornélie (1594), along with the play Soliman and Perseda. Plays disputedly attributed, in whole or in part, to Kyd include King Leir, Fair Em, Arden of Faversham and parts of 1 Henry VI and Edward III. A play related to The Spanish Tragedy called The First Part of Hieronimo (surviving in a quarto of 1605) may be a bad quarto or memorial reconstruction of a play by Kyd, or it may be an inferior writer's burlesque of The Spanish Tragedy inspired by that play's popularity. Kyd is supposed by some to have been the author of a Hamlet, the precursor of the Shakespearean play (see: Ur-Hamlet).

The success of Kyd's plays extended to Europe. Versions of The Spanish Tragedy were popular in Germany and the Netherlands for generations. The influence of these plays on European drama was largely the reason for the interest in Kyd among German scholars in the nineteenth century.

Later life
From 1587 to 1593 Kyd was in the service of an unidentified noble, since, after his imprisonment in 1593 (see below), he wrote of having lost "the favours of my Lord, whom I haue servd almost theis vi yeres nowe". Proposed nobles include the Earl of Sussex, the Earl of Pembroke, Lord Strange. and Edward De Vere, 17th Earl of Oxford. He may have worked as a secretary, if he did not also write plays. Around 1591 Christopher Marlowe also joined this patron's service, and for a while Marlowe and Kyd shared lodgings, and perhaps even ideas.

On 11 May 1593 the Privy Council ordered the arrest of the authors of "divers lewd and mutinous libels" which had been posted around London. One libel was found on the property of a Dutch Church and contained violent anti-foreigner sentiments and multiple allusions to the works of Marlowe. The next day, Kyd was among those arrested; he would later believe that he had been the victim of an informer. His lodgings were searched and instead of evidence of the "libels" there was found an Arianist tract, described by an investigator as "vile heretical conceits denying the eternal deity of Jesus Christ found amongst the papers of Thos. Kydd  [sic], prisoner ... which he affirmeth he had from C. Marley  [sic]". Historians such as Frederick Boas believe that Kyd was tortured brutally to obtain this information. Kyd told authorities the writings found in his possession belonged to Christopher Marlowe, a fellow dramatist and former roommate. Kyd “accused his former roommate of being a blasphemous traitor, an atheist who believed that Jesus Christ was a homosexual,” an uninformed confusion over the Arian and Early Gnostic concept of homoousios. Following the accusation, Marlowe was summoned by the Privy Council and, while waiting for a decision on his case, was killed in an incident in Deptford involving known government agents.

Kyd was eventually released but was not accepted back into his lord's service. Believing he was under suspicion of atheism himself, he wrote to the Lord Keeper, Sir John Puckering, protesting his innocence, but his efforts to clear his name were apparently fruitless. The last we hear from the playwright is the publication of Cornelia early in 1594. In the dedication to the Countess of Sussex he alludes to the "bitter times and privy broken passions" he had endured. Kyd died later that year at the age of 35, and was buried on 15 August in St Mary Colechurch in London. In December of that same year, Kyd's mother legally renounced the administration of his estate, probably because it was debt-ridden.

St Mary Colechurch was destroyed in the Great Fire of London in 1666, and not rebuilt.

Works
The dates of composition are approximate.

 * Don Horatio (partially extant in The First Part of Hieronimo, c. 1586)
 * The Spanish Tragedy (c. 1587)
 * The Householder's Philosophy (translation, 1588)
 * The Murder of John Brewen (pamphlet, 1592)
 * Arden of Faversham (attributed, 1592)
 * Solyman and Perseda (attributed, c. 1593)
 * Cornelia (translation of Robert Garnier, 1594)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Thomas Kyd


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Early texts of Shakespeare's works

The earliest texts of William Shakespeare's works were published during the 16th and 17th centuries in quarto or folio format. Folios are large, tall volumes; quartos are smaller, roughly half the size. The publications of the latter are usually abbreviated to Q1, Q2, etc., where the letter stands for "quarto" and the number for the first, second, or third edition published.

Plays
Eighteen of the 36 plays in the First Folio were printed in separate and individual editions prior to 1623. Pericles (1609) and The Two Noble Kinsmen (1634) also appeared separately before their inclusions in folio collections (the Shakespeare Third Folio and the second Beaumont and Fletcher folio, respectively). All of these were quarto editions, with two exceptions: The True Tragedy of Richard Duke of York, the first edition of Henry VI, Part 3, was printed in octavo form in 1595, as was the 1611 edition of The most lamentable tragedy of Titus Andronicus. In chronological order, these publications were:

 * Titus Andronicus, 1594, 1600, 1611 (octavo)
 * Henry VI, Part 2, 1594, 1600, 1619
 * Henry VI, Part 3, 1595 (octavo), 1600, 1619
 * Edward III, 1596
 * Romeo and Juliet, 1597, 1599, 1609
 * Richard II, 1597, 1598, 1608, 1615
 * Richard III, 1597, 1598, 1602, 1605, 1612, 1622
 * Love's Labour's Lost, 1598
 * Henry IV, Part 1, 1598, 1599, 1604, 1608, 1613, 1622
 * Henry IV, Part 2, 1600
 * Henry V, 1600, 1602, 1619
 * The Merchant of Venice, 1600, 1619
 * A Midsummer Night's Dream, 1600, 1619
 * Much Ado About Nothing, 1600
 * The Merry Wives of Windsor, 1602, 1619
 * Hamlet, 1603, 1604, 1611
 * King Lear, 1608, 1619
 * Troilus and Cressida, 1609
 * Pericles, Prince of Tyre, 1609, 1611, 1619
 * Othello, 1622
 * The Two Noble Kinsmen, 1634.

Six of the preceding were classified as "bad quartos" by Alfred W. Pollard and other scholars associated with the New Bibliography. Popular plays like 1 Henry IV and Pericles were reprinted in their quarto editions even after the First Folio appeared, sometimes more than once.

Poetry
Shakespeare's poems were also printed in quarto or octavo form:
 * Venus and Adonis, Q1—1593, Q2—1594 (with later editions in octavo);
 * The Rape of Lucrece, Q—1594 (with later editions in octavo);
 * The Phoenix and the Turtle, Q1—1601, Q2—1611 (in Robert Chester's Love's Martyr);
 * The Sonnets and A Lover's Complaint, Q—1609.

Differing from the quartos of the plays, the first editions of Shakespeare's narrative poems are extremely well printed. "Richard Field, Shakespeare's first publisher and printer, was a Stratford man, probably a friend of Shakespeare, and the two produced an excellent text." Shakespeare may have had direct involvement in the publication of the two poems, a check such as Ben Jonson exercised in reference to the publication of his works, but as Shakespeare clearly did not do in connection with his plays.

John Benson published a collected edition of Shakespeare's Poems in 1640; the poems were not added to collections of the plays until the 18th century. (The disputed miscellany The Passionate Pilgrim was only printed in octavo: twice in 1599, with another in 1612, all by William Jaggard.)

Folios

The folio format was reserved for expensive, prestigious volumes. During Shakespeare's lifetime, stage plays were not generally taken seriously as literature and not considered worthy of being collected into folios, so the plays printed while he was alive were printed as quartos. His poems were never included in his collected works until the eighteenth century.

It was not until 1616, the year of Shakespeare's death, that Ben Jonson defied convention by issuing a folio collection of his own plays and poems. Seven years later the folio volume Mr. William Shakespeare's Comedies, Histories & Tragedies appeared; this edition is now called the First Folio. It contains 36 plays, 18 of which were printed for the first time. Because Shakespeare was dead, the folio was compiled by John Heminges and Henry Condell (fellow actors in Shakespeare's company), and arranged into comedies, histories and tragedies. The First Folio is generally looked to by actors and directors as the purest form of Shakespeare's text. While punctuation and grammar are not always accurate by today's rules, these things served as direction to the actors on how to say the lines.

The First Folio was compiled by Heminges and Condell but published by a trio of stationers (booksellers and publishers): William Jaggard, his son Isaac Jaggard, and Edward Blount. William Aspley and John Smethwick participated in the endeavor as subsidiary partners. It contained, in addition to blandishments provided by various admirers of Shakespeare, such as the dedication signed by "John Heminge and Henry Condell", 36 plays. They included Troilus and Cressida, which was not, however, listed in the table of contents, but omitted Pericles and The Two Noble Kinsmen, which are now usually considered canonical. The Jaggards were printers, and did the actual printing of the book. The elder Jaggard has seemed an odd choice to many commentators, given his problematical relationship with the Shakespeare canon: Jaggard issued the suspect collection The Passionate Pilgrim in 1599 and 1612, and in 1619 printed the so-called False Folio, ten pirated or spurious Shakespearean plays, some with false dates and title pages. It is thought that the printing of the First Folio was such an enormous task that the Jaggards' shop was simply needed to get the job done. William Jaggard was old, infirm, and blind by 1623, and in fact died a month before the First Folio was complete.

The First Folio was reprinted three times in the 17th century:

The Second Folio appeared in 1632. Isaac Jaggard had died in 1627, and Edward Blount had transferred his rights to stationer Robert Allot in 1630. The Second Folio was published by Allot, William Aspley, Richard Hawkins, Richard Meighen, and John Smethwick, and printed by Thomas Cotes. It contained the same plays as the First Folio and much of the same additional material, with the addition of an unsigned poem by John Milton.

The Third Folio was issued in 1663, published by Philip Chetwinde; Chetwinde had married Robert Allot's widow and so obtained the rights to the book. To the second impression of the Third Folio (1664) he added seven plays, namely Pericles, Prince of Tyre; Locrine; The London Prodigal; The Puritan; Sir John Oldcastle; Thomas Lord Cromwell; and A Yorkshire Tragedy. (See: Shakespeare Apocrypha.) All seven of these additional plays had been published as quartos while Shakespeare was alive, but only Pericles was eventually widely accepted into the Shakespearean canon.

The quartos of Pericles (1609 and 1611), The London Prodigal (1605) and A Yorkshire Tragedy (1608) were all attributed to William Shakespeare on their front pages. The quartos of Locrine (1595), The Puritan (1607) and Thomas Lord Cromwell (1602 and 1613) were attributed to W. S. on their title pages, but Shakespeare was not the only playwright with those initials; Wentworth Smith has been put forward as another possible author of these works. Sir John Oldcastle was printed in 1619, three years after Shakespeare's death, as part of the False Folio. It was attributed to Shakespeare on its title page which also bore a false date of 1600.

The Third Folio is relatively rare, compared to the Second and Fourth, probably because unsold copies were destroyed in the Great Fire of London in 1666. One surviving copy was purchased by the Irish High Court judge and antiquarian William O'Brien in the 1880s. It was put up for auction by Sotheby's in 2017.

The Fourth Folio appeared in 1685, published by R. Bentley, E. Brewster, R. Chiswell, and H. Herringman. It contains the same 43 plays as the Third Folio. Brewster, Chiswell, and Herringman were members of the six-man syndicate that published the third Ben Jonson folio in 1692; Herringman was one of three stationers who issued the second Beaumont and Fletcher folio in 1679.

The Fourth Folio in turn served as the base for the series of eighteenth-century editions of Shakespeare's plays. Nicholas Rowe used the Fourth Folio text as the foundation of his 1709 edition, and subsequent editors — Pope, Theobald, etc. — both adapted and reacted to Rowe's text in their own editions. (See: Shakespeare's editors.)

The Two Noble Kinsmen did not appear in any Folio edition. It was not printed until 1634, although there is evidence of its being performed much earlier. The title page said "written by the memorable worthies of their time: Mr. John Fletcher and Mr. William Shakspeare [sic], Gent." It was not included in most editions of Shakespeare (e.g., the Cambridge/Globe editions of Wright and Clark, ca. 1863) until the latter half of the 19th century (it appears, e.g., in Dyce's collected Works of Shakespeare in 1876) but it was not generally accepted into the Shakespeare canon until well into the 20th century, when, for example, it was included in the Riverside edition of 1974.

title: Early texts of Shakespeare's works


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Evil clown

The evil clown, or creepy clown, also known as the killer clown if their character revolves around murder, is a subversion of the traditional comic clown character, in which the playful trope is instead depicted in a more disturbing nature through the use of horror elements and dark humor. The modern archetype of the evil clown was popularized by the DC Comics supervillain Joker starting in 1940, and again by Pennywise in Stephen King's It. The character can be seen as playing on the sense of unease felt by sufferers of coulrophobia, the fear of clowns.

Origins
The modern archetype of the evil clown has unclear origins; the stock character appeared infrequently during the 19th century, in such works as Edgar Allan Poe's "Hop-Frog", which is believed by Jack Morgan, of the University of Missouri-Rolla, to draw upon an earlier incident "at a masquerade ball", in the 14th century, during which "the King and his frivolous party, costumed—in highly flammable materials—as simian creatures, were ignited by a flambeau and incinerated, the King narrowly escaping in the actual case." Evil clowns also occupied a small niche in drama, appearing in the 1874 work La femme de Tabarin by Catulle Mendès and in Ruggero Leoncavallo's Pagliacci (accused of being a plagiarism of Mendès' piece), both works featuring murderous clowns as central characters.

American serial killer and rapist John Wayne Gacy became known as the Killer Clown when arrested in 1978, after it was discovered he had performed as Pogo the Clown at children's parties and other events; however, Gacy did not actually commit his crimes while wearing his clown costume. During the 1980s, the National Lampoon published a series of mock comic books in the pages of the magazine, entitled "Evil Clown", which featured a malevolent character named Frenchy the Clown.

Evil clown themes were occasionally found in popular music. Zal Cleminson, guitarist with the English rock band The Sensational Alex Harvey Band, wore black and white clown-style makeup and colorful clothes while on stage during the band's 1970s heyday, while his "happy-sad-happy" demeanor helped give their performances an edge of menace.

The evil clown archetype plays strongly off the sense of dislike it caused to inherent elements of coulrophobia; however, it has been suggested by Joseph Durwin that the concept of evil clowns has an independent position in popular culture, arguing that "the concept of evil clowns and the widespread hostility it induces is a cultural phenomenon which transcends just the phobia alone". A study by the University of Sheffield concluded "that clowns are universally disliked by children. Some found them quite frightening and unknowable." This may be because of the nature of clowns' makeup hiding their faces, making them potential threats in disguise; as a psychology professor at California State University, Northridge stated, young children are "very reactive to a familiar body type with an unfamiliar face". This natural dislike of clowns makes them effective in a literary or fictional context, as the antagonistic threat perceived in clowns is desirable in a villainous character.

Researcher Ben Radford, who published Bad Clowns in 2016 and is regarded as an expert on the phenomenon, writes that looking throughout history clowns are seen as tricksters, fools, and more; however, they always are in control, speak their minds, and can get away with doing so. When writing the book Bad Clowns, Radford found that professional clowns are not generally fond of the bad-clown (or evil-clown) persona. They see them as "the rotten apple in the barrel, whose ugly sight and smell casts suspicion on the rest of them," and do not wish to encourage or propagate coulrophobia. Yet, as Radford discovered, bad clowns have existed throughout history: Harlequin, the King's fool, and Mr. Punch. Radford argues that bad clowns have the "ability to change with the times" and that modern bad clowns have evolved into Internet trolls. They may not wear clown costume but, nevertheless, engage with people for their own amusement, abuse, tease and speak what they think of as the "truth" much like the court jester and "dip clowns" do using "human foibles" against their victims. Radford states that, although bad clowns permeate the media in movies, TV, music, comics, and more, the "good clowns" outnumber the bad ones. Research shows that most people do not fear clowns but actually love them and that bad clowns are "the exception, not the rule."

Interpretations
The concept of the evil clown is related to the irrational fear of clowns, known as coulrophobia, a neologism coined in the context of informal "-phobia lists".

The cultural critic Mark Dery has theorized the postmodern archetype of the evil clown in "Cotton Candy Autopsy: Deconstructing Psycho-Killer Clowns" (a chapter in his cultural critique The Pyrotechnic Insanitarium: American Culture on the Brink).

Tracking the image of the demented or deviant clown across popular culture, Dery analyzes the "Pogo the Clown" persona of the serial killer John Wayne Gacy; the obscene clowns of the neo-situationist Cacophony Society; the Joker (of Batman fame); the grotesque art of R.K. Sloane; the sick-funny Bobcat Goldthwait comedy Shakes the Clown; Scooby-Doo's Ghost Clown from the episode "Bedlam in the Big Top"; Horny the Clown in the 2007 horror-comedy movie Drive-Thru, and Pennywise from Stephen King's It.

Using Mikhail Bakhtin's theory of the carnivalesque, Jungian and historical writings on the images of the fool in myth and history, and ruminations on the mingling of ecstasy and dread in the Information Age, Dery asserts the evil clown is an icon of our times. Clowns are often depicted as murderous psychopaths at many American haunted houses.

Wolfgang M. Zucker points out the similarities between a clown's appearance and the cultural depictions of demons and other infernal creatures, noting "[the clown's] chalk-white face in which the eyes almost disappear, while the mouth is enlarged to a ghoulish bigness, looks like the mask of death".

According to psychology professor Joseph Durwin at California State University, Northridge, young children are "very reactive to a familiar body type with an unfamiliar face". Researchers who have studied the phobia believe there is some correlation to the uncanny valley effect. Additionally, clown behavior is often "transgressive" (anti-social behavior) which can create feelings of unease.

A 2022 survey of 987 adults from 64 countries found that 54% of respondents reported experiencing some degree of coulrophobia.

The clown sightings
The related urban legend of evil clown sightings in real life is known as "phantom clowns". First reported in 1981 in Brookline, Massachusetts, children said that men dressed up as clowns had attempted to lure them into a van. The panic spread throughout the US in the Midwest and Northeast. It resurfaced in 1985 in Phoenix, Arizona; in 1991 in West Orange, New Jersey; in 1990 in Brazil, through a story reported by the Brazilian tabloid Notícias Populares; and 1995 in Honduras. Later sightings included Chicago in Illinois in 2008. Explanations for the phenomenon have ranged from Stephen King's It and the crimes of serial killer John Wayne Gacy, to a moral panic influenced by contemporaneous fears of Satanic ritual abuse. It also shows similarities to the story of the Pied Piper of Hamelin. In most cases the reports were made by children, and no adults or police officers were able to confirm the sightings.

In 2013, a character who became known as "the Northampton Clown" was repeatedly sighted standing silently around the English town. The work of three local filmmakers, Alex Powell, Elliot Simpson and Luke Ubanski, the Northampton clown was similar in appearance to Pennywise from Stephen King's It. Although rumors said that the clown may have a knife, the clown himself denied these rumors through social media. In March 2014, Matteo Moroni from Perugia, Italy, owner of YouTube channel DM Pranks, began dressing up as a killer clown and terrifying unsuspecting passers-by, with his videos racking up hundreds of millions of views. In 2014, further complaints of evil clown pranksters were reported in France, the United States and Germany, possibly inspired by American Horror Story: Freak Show.

In 2014, "the Wasco clown" attracted social media attention in California. Again this clown shared a similar resemblance to Pennywise, and it was revealed that the social media postings were part of a year-long photography project conducted by the artist's wife. In Bakersfield, California "menacing" clowns were reported, some with weapons. In July 2015, a "creepy" clown was seen around a local cemetery in Chicago and terrorizing anyone in the graveyard.

There was another burst of such sightings in 2016, including in South Carolina and New York.

Researcher Ben Radford writes that there have been many surges of evil clown sightings reported, Radford says it is most likely pranksters. The urban legends and panic can cause real danger as "face-painted pranksters and innocent bystanders may be at risk" by interaction of well-intended public or police thinking a threat exists when it does not.

Response to evil clowns in media
In 2014, Clowns of America International responded to the depiction of Twisty on American Horror Story, and evil clowns in media generally. President Glenn Kohlberger said, "Hollywood makes money sensationalizing the norm. They can take any situation no matter how good or pure and turn it into a nightmare. ... We do not support in any way, shape or form any medium that sensationalizes or adds to coulrophobia or 'clown fear.

Depictions
The contemporary "evil clown" archetype developed in the 1980s, notably popularized by Stephen King's It, and perhaps influenced by John Wayne Gacy, a serial killer dubbed the Killer Clown in 1978. Killer Klowns from Outer Space is a 1988 horror comedy dedicated to the topic. The Joker character in the Batman franchise was introduced in 1940 and has developed into one of the most recognizable and iconic fictional characters in popular culture, leading Wizard magazine's "100 Greatest Villains of All Time" ranking in 2006. Although Krusty the Clown, a cartoon character introduced 1989 in the animated sitcom The Simpsons, is a comical, non-scary clown, the character reveals darker aspects in his personality. In The Simpsons episode "Lisa's First Word" (1992), children's fear of clowns features in the form of a very young Bart being traumatized by an inexpertly built Krusty the Clown themed bed, repeatedly uttering the phrase "can't sleep, clown will eat me...." The phrase inspired an Alice Cooper song in the album Dragontown (2001) and became a popular catchphrase. Evil clowns are also mentioned in a popular song by P!nk.

The American rap duo Insane Clown Posse have exploited this theme since 1989 and have inspired Twiztid and similar acts, many on Psychopathic Records, to do likewise. Websites dedicated to evil clowns and the fear of clowns appeared in the late 1990s.

 * The Joker, the nemesis of Batman, whose key features are chalk-white skin, emerald-green hair, ruby-red lips and (in some iterations) a perpetual smile, sometimes a permanent sardonic grin or a Glasgow smile, depending on the adaption of the character. He is commonly depicted as a criminal mastermind, as well as a sadistic and murderous psychopath. The character is also known by several nicknames, including "the Clown Prince of Crime".
 * The 1982 film Poltergeist, directed by Tobe Hooper and produced by Steven Spielberg, along with the 2015 remake of the same name directed by Gil Kenan, feature a possessed clown doll.
 * Pennywise the Dancing Clown, the main antagonist in Stephen King's 1986 horror novel It and its adaptations. Pennywise was portrayed in the 1990 television miniseries version by Tim Curry and by Bill Skarsgård in the 2017 film adaptation and its 2019 sequel.
 * The 1988 film Killer Klowns from Outer Space, directed by the Chiodo Brothers, features extraterrestrial evil clowns as the story's antagonists.
 * The 1989 film Clownhouse, written and directed by Victor Salva, concerns brothers who are attacked in their own home by escaped mental patients dressed as clowns.
 * The most famous professional wrestling depiction of an evil clown was Doink the Clown, a persona originated in 1992 by professional wrestler Matt Osborne in the World Wrestling Federation. Originally, the gimmick was that of a sadistic, evil clown, playing cruel tricks on fans and wrestlers to amuse himself and put them off guard; to help gain heat for the character, he was placed in a storyline feud with Crush, wherein Doink, after faking an injury, sneak-attacked Crush with a loaded prosthetic arm. The evil clown gimmick would be dropped later in 1993 as he turned face.
 * Violator, a supervillain demon appearing in the Spawn comic books published by Image Comics, is commonly depicted in the form of "Clown", a balding, overweight man with blue facepaint.
 * Sweet Tooth, a character in the Twisted Metal video game series. Sweet Tooth the Clown from Twisted Metal (2012) is a man wearing a psychotic clown mask with a flaming head and carrying a large machete. He drives a weaponised ice-cream van with the same clown face on the roof.
 * Jack the Clown, an icon of the Halloween Horror Nights event celebrated at Universal Studios Florida, Universal Studios Hollywood, Universal Studios Singapore, and Universal Studios Japan.
 * The 2009 BBC comedy programme Psychoville features a protagonist named Mr Jelly, "[a]n embittered hook-handed clown and children's entertainer."
 * The horror film series Killjoy features a demonic killer clown as its main antagonist.
 * In the 2012 anthology horror film Scary or Die, a drug dealer is bitten by a clown at a birthday party, and he begins to transform into a cannibalistic clown himself.
 * The 2012 film Stitches features a murderous birthday clown, portrayed by Ross Noble, who is resurrected from the dead in order to enact revenge upon the children who contributed to his death.
 * The 2013 horror film All Hallows' Eve, the 2016 film Terrifier and its subsequent sequels feature a homicidal clown named Art the Clown.
 * The FX horror anthology series American Horror Story used two instances of evil clowns: The first being Twisty the Clown from the fourth season Freak Show, who made a cameo appearance in Cult where the season's antagonist created a murderous clown cult to orchestrate his rise to political power.
 * The 2014 film Theatre of Fear, directed by Andrew Jones, features a murderous clown character played by Nathan Head.
 * The 2014 horror film Clown, directed by Jon Watts and produced by Eli Roth, follows a man who, upon finding and wearing a clown suit, becomes trapped in the cursed skin of an ancient Nordic demon known as the "Clöyne".
 * The 2017 film Behind the Sightings was inspired by the viral clown sightings of 2016.

title: Evil clown


text:
Everyman (15th-century play)

The Somonyng of Everyman (The Summoning of Everyman), usually referred to simply as Everyman, is a late 15th-century morality play by an anonymous English author, printed circa 1530. It is possibly a translation of the Dutch play Elckerlijc (Everyman).

Like John Bunyan's 1678 Christian novel The Pilgrim's Progress, Everyman uses allegorical characters to examine the question of Christian salvation and what Man must do to attain it.

Summary
The plot is about how the good and evil deeds of one's life will be tallied by God after death, as in a ledger book. The play is the allegorical accounting of the life of Everyman, who represents all mankind. In the course of the action, Everyman tries to convince other characters to accompany him in the hope of improving his life. All the characters are also mystical; the conflict between good and evil is shown by the interactions between the characters. Everyman is being singled out because it is difficult for him to find characters to accompany him on his pilgrimage. Everyman eventually realizes through this pilgrimage that he is essentially alone, despite all the personified characters that were supposed necessities and friends to him. Everyman learns that when you are brought to death and placed before God, all you are left with are your own good deeds.

Setting
The cultural setting is based on the Roman Catholicism of the era. Everyman attains afterlife in heaven by means of good works and the Catholic Sacraments, in particular Confession, Penance, Unction, Viaticum and receiving the Eucharist.

Synopsis
The oldest surviving example of the script begins with this paragraph on the frontispiece:
 * {| class=wikitable

After a brief prologue asking the audience to listen, God speaks, lamenting that humans have become too absorbed in material wealth and riches to follow Him, so He commands Death to go to Everyman and summon him to heaven to make his reckoning. Death arrives at Everyman's side to tell him it is time to die and face judgment. Upon hearing this, Everyman is distressed, so begs for more time. Death denies this, but will allow Everyman to find a companion for his journey.
 * Here begynneth a treatyſe how þe hye Fader of Heuen ſendeth Dethe to ſomon euery creature to come and gyue a counte of theyr lyues in this worlde, and is in maner of a morall playe.
 * Here begins a treatise how the high Father of Heaven sends Death to summon every creature to come and give account of their lives in this world, and is in the manner of a moral play.
 * }

Everyman's friend Fellowship promises to go anywhere with him, but when he hears of the true nature of Everyman's journey, he refuses to go. Everyman then calls on Kindred and Cousin and asks them to go with him, but they both refuse. In particular, Cousin explains a fundamental reason why no people will accompany Everyman: they have their own accounts to write as well. Afterwards, Everyman asks Goods, who will not come: God's judgment will be severe because of the selfishness implied in Goods's presence.

Everyman then turns to Good Deeds, who says she would go with him, but she is too weak as Everyman has not loved her in his life. Good Deeds summons her sister Knowledge to accompany them, and together they go to see Confession. In the presence of Confession, Everyman begs God for forgiveness and repents his sins, punishing himself with a scourge. After his scourging, Everyman is absolved of his sins, and as a result, Good Deeds becomes strong enough to accompany Everyman on his journey with Death.

Good Deeds then summons Beauty, Strength, Discretion and Five Wits to join them, and they agree to accompany Everyman as he goes to a priest to take sacrament. After the sacrament, Everyman tells them where his journey ends, and again they all abandon him – except for Good Deeds. Even Knowledge cannot accompany him after he leaves his physical body, but will stay with him until the time of death.

Content at last, Everyman climbs into his grave with Good Deeds at his side and dies, after which they ascend together into heaven, where they are welcomed by an Angel. The play closes as the Doctor enters and explains that in the end, a man will only have his Good Deeds to accompany him beyond the grave.

Adaptations
A modern stage production of Everyman did not appear until July 1901 when The Elizabethan Stage Society of William Poel gave three outdoor performances at the Charterhouse in London. Poel then partnered with British actor Ben Greet to produce the play throughout Britain, with runs on the American Broadway stage from 1902 to 1918, and concurrent tours throughout North America. These productions differed from past performances in that women were cast in the title role, rather than men. Film adaptations of the 1901 version of the play appeared in 1913 and 1914, with the 1913 film being made with an early color two-process, Kinemacolor.

A version was filmed for Australian TV in 1964.

Another well-known version of the play is Jedermann by the Austrian playwright Hugo von Hofmannsthal, which has been performed annually at the Salzburg Festival since 1920, and adapted into film several times. Jedermann received an English language adaptation in 1917, The Play of Everyman. The 1917 adaptation was performed at the Trinity Auditorium in Los Angeles, followed by a run at the Burbank Theater in Burbank, California, and was translated and adapted by George Sterling with "Richard" Ryszard Ordynski and music by Victor Schertzinger. The Sterling adaptation was performed again in 1936 at the Hollywood Bowl with music by Einar Nelson.

Frederick Franck published a modernised version of the tale entitled "Everyone", drawing on Buddhist influence.

A direct-to-video film of Everyman was made in 2002, directed by John Farrell, which updated the setting to the early 21st century, including Death as a businessman in dark glasses with a briefcase, and Goods being played by a talking personal computer.

Jo Clifford's play Every One, a modern version of Everyman, premiered at the Royal Lyceum Theatre in Edinburgh in 2010.

In 2014, London theatre company Scena Mundi Theatre (then Little Spaniel Theatre) staged a production of Everyman at St Bartholomew the Great, a Church in the City of London. The play, directed by Cecilia Dorland, played on the church's medieval setting and kept the Middle English text intact. A strong ensemble piece using music and singing, it was very well received by critics.

A modernized adaptation by Carol Ann Duffy, the Poet Laureate of the United Kingdom, with Chiwetel Ejiofor in the title role, was performed at the National Theatre from April to July 2015.

In December 2016, Moravian University in Bethlehem, Pennsylvania presented Everyman on Trial, a contemporary adaptation written and directed by Christopher Shorr.

Branden Jacobs-Jenkins' adaptation, titled Everybody, premiered in 2017 at the Pershing Square Signature Center in New York City.

title: Everyman (15th-century play)


text:
Karplus–Strong string synthesis

Karplus–Strong string synthesis is a method of physical modelling synthesis that loops a short waveform through a filtered delay line to simulate the sound of a hammered or plucked string or some types of percussion.

At first glance, this technique can be viewed as subtractive synthesis based on a feedback loop similar to that of a comb filter for z-transform analysis. However, it can also be viewed as the simplest class of wavetable-modification algorithms now known as digital waveguide synthesis, because the delay line acts to store one period of the signal.

Alexander Strong invented the algorithm, and Kevin Karplus did the first analysis of how it worked. Together they developed software and hardware implementations of the algorithm, including a custom VLSI chip. They named the algorithm "Digitar" synthesis, as a portmanteau for "digital guitar".

How it works

 * 1) A short excitation waveform (of length L samples) is generated. In the original algorithm, this was a burst of white noise, but it can also include any wideband signal, such as a rapid sine wave chirp or frequency sweep, or a single cycle of a sawtooth wave or square wave.
 * 2) This excitation is output and simultaneously fed back into a delay line L samples long.
 * 3) The output of the delay line is fed through a filter.  The gain of the filter must be less than 1 at all frequencies, to maintain a stable positive feedback loop. The filter can be a first-order lowpass filter (as pictured).  In the original algorithm, the filter consisted of averaging two adjacent samples, a particularly simple filter that can be implemented without a multiplier, requiring only shift and add operations. The filter characteristics are crucial in determining the harmonic structure of the decaying tone.
 * 4) The filtered output is simultaneously mixed into the output and fed back into the delay line.

Tuning the string
The fundamental frequency (specifically, the lowest nonzero resonant frequency) of the resulting signal is the lowest frequency at which the unwrapped phase response of the delay and filter in cascade is $$-2\pi$$. The required phase delay D for a given fundamental frequency F0 is therefore calculated according to D = Fs/F0 where Fs is the sampling frequency.

The length of any digital delay line is a whole-number multiple of the sampling period. In order to obtain a fractional delay often needed for fine tuning the string below JND (Just Noticeable Difference), interpolating filters are used with parameters selected to obtain an appropriate phase delay at the fundamental frequency. Either IIR or FIR filters may be used, but FIR have the advantage that transients are suppressed if the fractional delay is changed over time. The most elementary fractional delay is the linear interpolation between two samples (e.g., s(4.2) = 0.8s(4) + 0.2s(5)). If the phase delay varies with frequency, harmonics may be sharpened or flattened relative to the fundamental frequency. The original algorithm used equal weighting on two adjacent samples, as this can be achieved without multiplication hardware, allowing extremely cheap implementations.

Z-transform analysis can be used to get the pitches and decay times of the harmonics more precisely, as explained in the 1983 paper that introduced the algorithm.

A demonstration of the Karplus-Strong algorithm can be heard in the following Vorbis file. The algorithm used a loop gain of 0.98 with increasingly attenuating first order lowpass filters. The pitch of the note was A2, or 220 Hz.

Holding the period (= length of the delay line) constant produces vibrations similar to those of a string or bell. Increasing the period sharply after the transient input produces drum-like sounds.

Refinements to the algorithm
Due to its plucked-string sound in certain modes, Alex Strong and Kevin Karplus conjectured that the Karplus-Strong (KS) algorithm was in some sense a vibrating string simulation, and they worked on showing that it solved the wave equation for the vibrating string, but this was not completed. Julius O. Smith III recognized that the transfer-function of the KS, when viewed as a digital filter, coincided with that of a vibrating string, with the filter in the feedback loop representing the total string losses over one period. He later derived the KS algorithm as a special case of digital waveguide synthesis, which was used to model acoustic waves in strings, tubes, and membranes. The first set of extensions and generalizations of the Karplus-Strong Algorithm, typically known as the Extended Karplus-Strong (EKS) Algorithm, was presented in a paper in 1982 at the International Computer Music Conference in Venice, Italy, and published in more detail in 1983 in Computer Music Journal in an article entitled "Extensions of the Karplus Strong Plucked String Algorithm," by David A. Jaffe and Julius O. Smith, and in Smith's PhD/EE dissertation.

Alex Strong developed a superior wavetable-modification method for plucked-string synthesis, but only published it as a patent.

Musical applications
The first musical use of the algorithm was in the work May All Your Children Be Acrobats written in 1981 by David A. Jaffe, and scored for eight guitars, mezzo-soprano and computer-generated stereo tape, with a text based on Carl Sandburg's The People, Yes. Jaffe continued to explore the musical and technical possibilities of the algorithm in Silicon Valley Breakdown, for computer-generated plucked strings (1982), as well as in later works such as Telegram to the President, 1984 for string quartet and tape, and Grass for female chorus and tape (1987).

The patent was licensed first to Mattel Electronics, which failed as a company before any product using the algorithm was developed, then to a startup company founded by some of the laid-off Mattel executives. They never got sufficient funding to finish development, and so never brought a product to market either. Eventually Yamaha licensed the patent, as part of the Sondius package of patents from Stanford. It is unknown whether any hardware using the algorithm was ever sold, though many software implementations (which did not pay any license fees to the inventors) have been released.

While they may not adhere strictly to the algorithm, many hardware components for modular systems have been commercially produced that invoke the basic principles of Karplus-Strong Synthesis: using an inverted, scaled control system for very small time values in a filtered delay line to create playable notes in the Western Tempered tuning system, controlled with volt per octave tracking or MIDI data. The Inventors were not specifically credited, though the term "Karplus-Strong Synthesis" is referenced in some of the manuals.

Hardware components capable of Karplus-Strong style synthesis include the Moog Clusterflux 108M, Mutable Instruments Elements and Rings, 4ms Company Dual Looping Delay, 2HP Pluck, Make Noise Mimeophon, Arturia MicroFreak, Non Linear Circuits Is Carp Lust Wrong?, and the Strymon Starlab.

title: Karplus–Strong string synthesis


text:
Morality play

The morality play is a genre of medieval and early Tudor drama. The term is used by scholars of literary and dramatic history to refer to a genre of play texts from the fourteenth through sixteenth centuries that feature personified concepts (most often virtues and vices, but sometimes practices or habits) alongside angels and demons, who are engaged in a struggle to persuade a protagonist who represents a generic human character toward either good or evil. The common story arc of these plays follows "the temptation, fall and redemption of the protagonist".

English morality plays
Hildegard von Bingen's Ordo Virtutum (English: "Order of the Virtues"), composed c. 1151 in Germany, is the earliest known morality play by more than a century, and it is the only medieval musical drama to survive with an attribution for both the text and the music. Because there are many formal differences between this play and later medieval moralities, as well as the fact that it only exists in two manuscripts, it is unlikely that the Ordo Virtutum had any direct influence on the writing of its later English counterparts.

Traditionally, scholars name only five surviving English morality plays from the medieval period: The Pride of Life (late 14th century), The Castle of Perseverance (c.1425); Wisdom, (1460–63); Mankind (c.1470); Everyman (1510). The Pride of Life was the earliest record of a morality play written in the English language; the text (destroyed by fire in 1922, but published earlier) existed on the back of a parchment account roll from June 30, 1343, to January 5, 1344, from the Priory of the Holy Trinity in Dublin. However, this textual record was incomplete. The play cut off mid-line, when the character Messenger, at the command of the King, called upon Death; the plot summary provided by the introductory banns, featured at the beginning of the play, indicated that the action continued.

The Castle of Perseverance, Wisdom, and Mankind are all part of a single manuscript called the Macro Manuscript, named after its first known owner, Cox Macro of Bury St Edmunds. A second copy of the first 752 lines of Wisdom is preserved in MS Digby 133. It is possible that the Macro version was copied from the Digby manuscript, but there is also the possibility that both were copied from elsewhere. Unlike The Pride of Life and the Macro plays, all of which survive only in manuscript form, Everyman exists as a printed text, in four different sources. Two of these four sources were printed by Pynson and two were printed by John Skot. Pamela King notes how Everyman's status as a printed text pushes the boundaries of the medieval morality genre; she writes, "It was also one of the very first plays to be printed, and in some respects belongs more to the early Tudor tradition than that of the late Middle Ages."

Other English moralities include the fifteenth-century plays Occupation & Idleness and Henry Medwall's Nature, as well as an array of sixteenth-century works like The World and the Child and John Skelton's Magnificence. Additionally, there are other sixteenth-century plays that take on the typical traits of morality plays as outlined above, such as Hickscorner, but they are not generally categorized as such. The characters in Hickscorner are personified vices and virtues: Pity, Perseverance, Imagination, Contemplation, Freewill, and Hickscorner.

The French medieval morality play tradition is also quite rich: for an explanation of French medieval morality plays, visit the French Wikipedia page.

History of the term "morality play"
While scholars refer to these works as morality plays, the play texts do not refer to themselves as such; rather, the genre and its nomenclature have been retroactively conceived by scholarship as a way for modern scholars to understand a series of texts that share enough commonalities that they may be better understood together. Thus, as scholar Pamela King has noted, the morality plays' "absolute cohesion as a group" is "bound to be questioned in any attempt to define that form in its individual manifestations and theatrical contexts." As for the history of the term itself in modern usage, premodern plays were separated into 'moralities' and 'mysteries' by Robert Dodsley in the 18th century; he categorized moralities as allegorical plays and mysteries as biblical plays, though nothing suggests that the moralities are not biblical or would not conceive of themselves as such.

Although they do not explicitly label themselves with the genre title morality plays, some of the play texts self-reflexively refer to themselves with the term game. While the Middle English spelling of game varies, the noun generally refers to a joy, festivity, amusement, or play. In the opening lines of The Pride of Life, the Prolocutor uses the word game when asking his audience to listen attentively, stating, Lordinges and ladiis that beth hende, Herkenith al with mylde mode

[How ou]re gam schal gyn and ende (l. 5-7, emphasis added). In the closing lines of The Castle of Perseverance, the character Pater (meaning The Father) tells the audience, "Thus endyth oure gamys" (l. 3645).

While these plays appear to self-reflexively refer to their dramatic form, it is only Everyman that explicitly describes itself as a moral play, both in its incipit ("Here begynneth a treatyse... in maner of a morall playe") and when a character, Messenger, states that this literary work will communicate "By fygure [of] a morall playe" (l. 3). However, one should not interpret these self-reflexive lines as simply moments that identify the genre of morality plays. Although the lines use the word "playe," scholarship remains unsure if Everyman was actually staged as a dramatic performance, or if the text was a literary work intended for reading. The 1901 modern revival of the play, staged by Willian Poem, is the earliest record of the play's production. Additionally, Everyman is a translation of the Dutch Elckerlijc, and, therefore, is not originally an English literary work. Thus, due to the uncertainty regarding the play's status as a dramatic work, as well as the play's non-English origins, Everyman's self-reflective identification as a "morall playe" cannot confirm that the medieval moralities explicitly name themselves as a cohesive medieval morality genre.

Characteristics
Morality plays typically contain a protagonist who represents humanity as a whole, or an average layperson, or a human faculty; supporting characters are personifications of abstract concepts, each aligned with either good or evil, virtue or vice.

The clashes between the supporting characters often catalyze a process of experiential learning for the protagonist, and, as a result, provide audience members and/or readers with moral guidance, reminding them to meditate and think upon their relationship to God, as well as their social and/or religious community. Many, but not all, of the morality plays also encourage their audiences and/or readers to reflect upon the importance of penitential ritual.

Several academics have written upon these common thematic characteristics. Considering the plays' investment in staging the audience's/reader's relationship to God, Eleanor Johnson writes that Wisdom and Mankind, among several other medieval literary works, dramatically stage acts of contemplation to encourage the "cultivation of self-conscious participation in God and of awareness of God's participation in man," while "creating literary experiences that initiate work of spiritual contemplation." Additionally, Julie Paulson explores the plays' investment in relating penitential ritual and community; she writes, "In the moralities, it is impossible to split an interior self from the exterior practices and institutions that define it [...] By dramatizing their protagonists' fall and recovery through penance, the plays suggest how the experience of penitential ritual shapes penitents' understandings of the social and moral concepts central to the formation of Christian subjects." It is worth noting that Paulson, in making these summative comments, focuses her analysis on The Castle of Perseverance, the Macro plays, Everyman, and several moralities from the sixteenth century, and thus does not aim to characterize all moralities in her commentary.

Allegory and personification
Working to pinpoint a literary form that unites the moralities, the Oxford Dictionary of Literary Terms offers this definition: "Morality plays are dramatized allegories, in which personified virtues, vices, diseases, and temptations struggle for the soul of Man." The same book defines allegory as "a story or visual image with a second distinct meaning partially hidden behind its literal or visible meaning. The principal technique of allegory is personification, whereby abstract qualities are given human shape [...] allegory involves a continuous parallel between two (or more) levels of meaning in a story." While the Oxford Dictionary of Literary Terms uses the words allegory and personification in tandem with one another, the link between the two terms is a point of debate among scholars. Walter Melion and Bart M. Ramakers indicate that literary personifications are the building blocks for creating allegory: arguing for "personification as a mode of allegorical signification," Melion and Ramakers state, "As narrative, dramatic, or pictorial characters [personifications] develop a distinct reality," specifically, a reality that connects the literal and metaphorical interpretations of an allegory. However, Michael Silk insists that there is a fundamental difference between personification and allegory, as the representational figures within literary works are personifications that retain allegorical qualities. Additionally, Silk notes that "Various medievalists correctly insist that in antiquity and the Middle Ages the connection [between allegory and personification] is not made," indirectly complicating the notion that morality plays are allegorical constructions employing personified concepts.

While an allegorical literary form implies that literal and metaphorical elements must "continuously parallel" one another, these plays do not always allegorically parallel theological qualities/concepts and concrete action, but rather humanize abstract concepts—thereby emphasizing characters as personifications, but not allegorical constructions. For example, examining the character Mercy in Mankind, Pamela King notes, "Mercy the character begs God for the quality he represents, which is, strictly speaking, allegorical nonsense; he stands more for the human aegis by which mercy may be obtained, than for the quality itself." Similarly, Eleanor Johnson explains Mercy's humanity, implying his status as a personified concept: "Mercy suffers, Mercy trembles, Mercy is vulnerable; this is not an untouchable, impregnable Mercy [...] but rather a strikingly vulnerable and human one". Additionally, scholars complicate the notion that morality plays allegorically parallel the audience with the dramatic characters, indicating that the moralities actually incorporate the audience into the dramatic community. For example, writing on The Castle of Perseverance, Andrea Louise Young argues that the implied staging of the play (which includes the positioning of characters, as well as the placement of scaffolds and banners) encourages audience members to actively engage with the drama in a physical manner: "In moving around the play space, spectators can change the meaning of the drama for themselves and the other spectators." Young notes that the play invites audience members to enter the dramatic space and consequently position themselves through both "their eyes and their bodies," through where they choose to look and move in relation to the staged characters. King, Johnson, and Young indirectly show, without explicitly stating so, how the morality plays are not simply allegorical constructions, but rather fluid forms of personification that blur the distinctions between literal and metaphorical elements, characters and audience members/readers. Still, scholarship generally adopts the literary labels allegory, personification, and personification allegory to explain the morality plays' formal depiction of the relationship between the abstract realm of concepts and everyday circumstances of human life. Pamela King notes the "broadly allegorical" form unifying the moralities. King suggests that the plays employ an allegorical framework of personification to metaphorically parallel, and conceptually separate, "the ephemeral and imperfect world of everyday existence" from an abstract "eternal reality". While King indicates that the plays show the dramatic action to merely parallel and imitate eternal, abstract concepts, Julie Paulson argues that the moralities use personification allegory to reunite the concrete and the abstract. Paulson writes, "in giving a word such as 'wisdom' or 'mankind' a body and a voice, personification allegory instead returns us to the lived experiences and particular circumstances that give those words their meanings". Additionally, Paulson underscores that plays such as The Castle of Perseverance and Everyman employ protagonists that personify humankind in an allegorical parallel to the audiences and readers of the play. As one can see, different authors employ the literary terms allegory and personification to argue various conclusions about the plays' separation or unification of abstract and concrete realities.

Justice and Equity as characters
In early English dramas Justice was personified as an entity which exercised "theological virtue or grace, and was concerned with the divine pronouncement of judgment on man". However, as time progressed, more moralities began to emerge; it is during this transitional period where one begins to see Justice begin to assume more and more the qualities of a judge. The Justice in Respublica begins to concern himself with administering justice on "the criminal element", rather than with the divine pronouncement on a generic representative of mankind. This is the first instance where one may observe a direct divergence from the theological virtues and concerns that were previously exerted by Justice in the morality plays of the fifteenth century. The Justice in Respublica is personified as a "civil force rather than a theological one". An evolution of sorts takes place within the morals and agendas of Justice: he begins to don the Judicial Robe of prosecutor and executioner.

Another change envelops in the character of Justice during the sixteenth century in morality plays; Equity replaces Justice and assumes the judiciary duties previously performed by Justice. This changing of rulers, or preceding justices, is done when Equity declares that his brother Justice has been banished from the country and that he (Equity) will from now on take on the duties of the former monarch, Justice. This change of ruling heads is portrayed in the morality play, Liberality and Prodigality, where Equity serves Virtue in the detection, arrest, and punishment of Prodigality for the robbery and murder of Tenacity, a yeoman in the country of Middlesex. Virtue states, So horrible a fact can hardly pleaded for favour:

Therefore go you, Equity, examine more diligently

The manner of this outrageous robbery:

And as the same by examination shall appear,

Due justice may be done in presence here. (Liberality and Prodigality 377)

The meta phases that Justice undergoes during the sixteenth century in morality plays, from "Justice" to "Equity" further illustrates the evolution of Justice; not only did Justice change from a "theological abstraction to a civil servant", but he experienced a corporeal change as well.

One may readily observe the evolutionary progression of Justice as portrayed in the plays of the fifteenth and sixteenth centuries. One encounters Justice in the early-fifteenth-century moralities as a performer playing the role of a theological virtue or grace, and then one sees him develop to a more serious figure, occupying the position of an arbiter of justice during the sixteenth century. It is a journey of discovery and great change on which Justice welcomes one to embark as one leafs through the pages of morality plays.

Use of language and poetic technique
All of the morality plays, especially the Macro plays, show not only a mastery of language but also a light-hearted delight therein. All of the plays are written in some sort of end-rhymed verse, but with much variation, not only between the plays but in individual plays as well. Often verse is used to contrast the personalities of good and evil characters. For example, in Wisdom the characters Wysdom and Anima speak in "dignified, regular rhythm, almost always with four stresses" and the rhyme scheme ABABBCBC whereas "Lucifer prefers a tripping measure with two to five stress and only two rhymes." Other characters speak like Wisdom when under his influence and like Lucifer when under his. This system of contrastive verse is further refined in Mankind (Ramsay cxxxix). This is not the only use of variation in meter. For example, even without having to contrast with a good character's manner of talking, when Mankind ascends to World's scaffold in The Castle of Perseverance, Mundus, Voluptas, and Stultitia briefly switch from a four stress line to a faster and more excited two stress line (ll. 610–646), before returning to the four stress line after a scene change. Alliteration is put to wonderful effect in The Castle of Perseverance. It appears in every stanza of more than four lines, though this is not evenly distributed, with later debate scenes employing less alliteration and the characters World, Belial, Flesh, and the seven sins alliterating nearly all of their lines, a habit the character Mankind learns from them. This is not to imply that alliteration is purely the mark of an evil character, for the bad angel alliterates very little and the neutral flag bearers who provide a summary of events at the beginning of the play script make extensive use of alliteration. At many points this is for ornamental effect: Michael R. Kelley places this in the context of a flamboyant style originating in Franco-Burgundian culture. But that is not all the playwright does with the effect. Clare Wright argues convincingly that alliteration among other formal structures encourages the actors to perform with a "devilish corporeal register." She uses Belyal's first speech as an example: Now I sytte, Satanas, in my sad synne, (Now sit I, Satan, steadfast in my sin,)

As devyl dowty, in draf as a drake. (As devil doughty, like a dragon on my sack.) I champe and I chafe, I chocke on my chynne, (I champ and I chew and I thrust out my chin;) I am boystous and bold, as Belyal the blake. (I am boisterous and bold as Belial the black!) What folk that I grope thei gapyn and grenne, (The folk that I grasp they gasp and they groan,) Iwys, fro Carlylle into Kent my carpynge thei take, (From Carlisle to Kent, my carping they take!) Bothe the bak and the buttoke brestyth al on brenne, (Both the back and the buttocks burst burning unbound,) Wyth werkys of wreche I werke hem mykyl wrake. (With works of vengeance, them wretched I make.) In this speech, many of the alliterated phonemes are "aggressively plosive" and the /tʃ/ of "I champe and I chafe, I choke on my chynne" "requires the speaker to part his lips and bare his teeth, bringing them together in an expression that resembles the clenched-tooth grimace of the devil in contemporary iconography." While mostly written in Middle English, some of the plays employ Latin and French to wonderful effect, both thematically significant and just plain humorous. Latin, of course, as the language of the Roman Catholic Church, was naturally important for the sort of religious discourse these plays engaged in. That does not mean that the playwrights were unwilling to play with Latin. For example, in Mankind, the character Mercy has a highly Latinizing manner of speech: in terms of vocabulary and meticulously tidy versification and sentence structure, all of which culminates in what one scholar calls "inkhorn and churchily pedagogical." (Johnson 172). Mercy ends his first speech saying "I besech yow hertyly, have this premedytacyon" (l. 44), ending with a cumbersome Latin loanword. The first vice character on stage, Mischief, immediately picks up on Mercy's excessive Latinisms and continues with this end rhyme in order to mock Mercy's ornate speech: I beseche yow hertyly, leve yowr calcacyon. Leve yowr chaffe, leve yowr corn, leve yowr dalyacyon. Yowr wytt ys lytyll, yowr hede ys mekyll, ye are full of predycacyon (ll. 45-47). Shortly thereafter Mischief fully switches to a nonsense mixture of Latin and English to continue mocking Mercy's Latinizing, as well as to mangle Mercy's earlier reference to the parable of the wheat and tares: "Corn servit bredibus, chaffe horsibus, straw fyrybusque" (l. 57, translated: Corn serves bread, chaff horses, straw fires). The result of this is not only to show that the formal structures of Latin are nothing more than formal structures that can be spoofed and misused, but also to create a tone shift from stuffy seriousness to an amusement that "is central to the contemplative logic of the play" by showing how even Latin can be "dragged from the reaches of the church and into the mess of everyday life." There are many such examples of amusing nonsense Latin throughout the play.

In what is possibly most memorable of the vices' use of puns to twist good into bad, at one point in Mankind belt out a vibrant ditty on defecation that concludes, in a clear echo of 'holy holy holy,' with "Hoylyke, holyke, holyke! Holyke, holyke, holyke!", quite possibly a pun on 'hole-lick' or 'hole-leak'. Because of how this spoofs liturgical call-and-response worship as well as Nought's invitation, "Now I prey all the yemandry that ys here / To synge wyth us wyth a mery chere" (ll. 333–4), this is likely a moment of audience participation to highlight their own "susceptibilities to seduction by frivolity."

Finally, a peculiar trait that one will likely notice while reading these plays is the tendency of characters to describe in speech the actions they are (presumably) simultaneously performing as a way of verbally encoding stage directions. For example, in Mankind, the character Mankind says, "Thys earth wyth my spade I shall assay to delffe" (l. 328); this line, meaning, "This earth with my spade I will attempt to dig," appears to serve as a stage direction for Mankind's actor to literally dig. Besides simple actions, the same thing occurs in slapstick comedy or action scenes: when Mankind fights the vice-characters Nowadays, New Guise, and Nought, Mankind threatens to hit them with his shovel, saying, "Go and do yowr labur! Gode lett yow never the! / Or wyth my spade I shall yow dynge, by the Holy Trinyté!" (ll. 377–376); in response, New Guise says, "Alas, my jewellys! I shall be schent of my wyff!" (l. 381), directly indicating that Mankind has hit him as or right after he was threatening. This is not a trait restricted in the period to morality plays: a reason for the existence of this trait suggested by one scholar while discussing the Chester plays is that "A spectator who could see the action without hearing the lines would not have a significantly different experience from someone who could hear them."

Thematic characteristics
What binds morality plays together as a genre are the strong family resemblances between them. These resemblances are most strong in regard to personification allegory as a literary form. The plays also resemble each other in regard to thematic content. They feature other common characteristics that are not necessarily common to all texts within the genre. Particularly notable thematic commonalities include: the transitoriness of life in relation to the afterlife, the importance of divine mercy, the use of misprision by vice characters, and the inevitable cycle of sin and penitence found in the Macro plays and Henry Medwall's Nature (c. 1495). The emphasis on death in these plays underscores how to live a good life; in the medieval moralities and Medwall's Nature in particular, virtue characters encourage the generic human protagonist to secure a good afterlife by performing good deeds, practicing penitence, or asking for divine mercy before their death.

John Watkins also suggests that the principal vices in medieval morality plays, avarice, pride, extortion, and ambition, throw anxieties over class mobility into relief. Fifteenth-century plays like Occupation and Idleness and later morality plays (commonly considered Tudor interludes, like John Skelton's Magnyfycence) portray class-mobility positively. Whether for or against class mobility, morality plays engage with the subject. Other, smaller commonalities include audience participation, elaborate costuming, the virtue of labour, and the governance of the body/passions by the soul/reason in the service of Catholic virtue, money management, or the proper methods of governing a state.

The cohesion of the medieval morality play genre in particular is questionable as their family resemblances are loose in some instances. Despite being treated as the archetypal morality play, Everyman's plot has little in common with the other plays in the genre. That said, Everyman's straightforward focus on death, uninterested in the cycle of sin and penitence found in the Macro plays, resembles the Pride of Life. These two plays are less like the Macro plays than Medwall's Nature, which is not traditionally considered as a medieval morality play. Scholars such as Katherine Little, who claims that Everyman is not a medieval morality play, continue to pull at the genre's incohesive threading.

There are points of distinction in morality plays, beginning with Everyman, which can generally be attributed to humanism. According to Thomas Betteridge and Greg Walker, the majority of English dramas were religious in some form. However, plays are increasingly divorced from religion, and in particular, the staging of God and priests. While drama continued to contain religious themes, it was less and less often the case that religion was expressed directly. Betteridge and Walker also note that morality plays began to focus on the importance of education, specifically in regard to classical literature.

In Medwall's Nature, the opening speech prompts readings of Ovid and Aristotle. However, a strong focus on education can be found in Occupation and Idleness as well, which stages an errant schoolboy being taught to respect and learn from his teacher—this play is roughly contemporaneous with the Macro plays, suggesting that humanist trends are traceable in the morality play much earlier than Everyman. There is also a general, continuous increase in the individuation and complexity of characters. In Nature, a prostitute is given a regular name rather than the name of a concept. In Everyman, Everyman's mercantile language suggests a generic protagonist that represents a much smaller generic portion of humanity, '"every merchant," in juxtaposition to Mankind's earlier, full representation of all humanity. In Skelton's Magnyfycence, Magnificence and the vices that corrupt him represent a particular person, King Henry VIII, and his court 'minions' who were expelled for their poor behaviour.

Arundel's Constitutions
Scholars have long noted that the medieval morality plays were written after the creation of Arundel's Constitutions in 1407, whereby the Archbishop Thomas Arundel and his legislation sought to limit the preaching and teaching of religious matters, and outlawed any biblical translations into the vernacular. His Constitutions were written in explicit response to the threat of Lollardy. Since the morality plays do contain aspects of religious doctrine, such as the importance of penance and the salvation of the soul, scholars have questioned how it is that morality plays, in both the play-text and play form, continued to thrive throughout the fifteenth century. While scholars have not arrived at a satisfying conclusion, they nonetheless agree the morality plays were not seriously affected by the Constitutions, which suggests that either Arundel's Constitutions, the divide between Lollardy and orthodoxy, or the role that morality plays themselves played in society, continue to be somewhat misunderstood.

Decline
The recent trend in scholarship of the period in which morality plays were written is to admit the great degree of continuity between late medieval and Renaissance cultures of Europe. Nevertheless, although morality plays reach their apogee in the sixteenth century, religious drama of this sort and in general all but disappeared thereafter. The cause of this change can be traced to both changes in religious sensibilities related to the Protestant Reformation and more broadly changes in theatre as an industry in England.

Mid-Tudor Protestants continued writing religious plays that were recognizably different from their Catholic predecessors. For example, whereas earlier plays emphasize the importance of sacraments, plays by Protestants emphasize justification by faith alone, and even cast vice characters as Catholic.

The relationship between theatricality and doctrine was also found more troubled by Protestants. Earlier plays were criticized for their embellishments to biblical material, to which Protestant religious drama tried to adhere more closely. However, in many ways they were formally quite similar to their predecessors in ways that sat beside the tendencies they wished to resist, thus challenging any attempts by scholars to place the development of theater in the period in an evolutionary model.

With the opening of permanent and professional playhouses that were producing plays full time in the late sixteenth century, drama became "unmistakably an integral and compromised part of that same commercial culture" which earlier religious drama had criticized, and therefor "it could no longer seriously be maintained that it was primarily a pious activity." Thus, by the start of the seventeenth century a play like Everyman would be regarded "as at best a waste of time and at worst a sinful, 'popish' excess." However, this change "had the positive effect of creating the space for the artistic and commercial speculation of the public stage as it emerged at the end of the Tudor period." It is in this space that the now better-known William Shakespeare and Christopher Marlowe would do their work.

Pre-Reformation versus Post-Reformation
The outward purpose of all morality plays is to instruct listeners on the means of receiving redemption: a purpose that some plays adhere to relatively consistently, while others delight so extensively in their vices that broad entertainment establishes itself as an equally dominant raison d'etre. However, morality plays after the Protestant Reformation are of a distinctly different didacticism than the morality plays before the Reformation.

Whereas the didactic elements pre-Reformation morality plays usually reinforced the practices or doctrines of medieval Catholicism (often focusing on sacraments like penance), the post-Reformation morality plays—when they concerned themselves with religious doctrine, rather than more secular concerns about education or good living (as with John Redford's Play of Wit and Science) -- sometimes worked to destroy Catholic credibility and demonise the Catholic Church. Although many post-Reformation morality plays were often like their predecessors in that they also were concerned with the salvation of its audience (and in their tendency to allow playful depictions of vice to eclipse those concerns), they differed in that they believed that the theology promoted by pre-Reformation plays was antithetical to salvation. Thus, a major shift in focus, from concern for the individual's moral behaviour to concern for the individual's theological practices, occurred with the post-Reformation morality plays. The wave of Protestantism which fuelled the content of these plays dictated that more attention should be given to warning people against the Catholic Church than of their sinful nature. The means of redemption, according to the philosophy embedded in post-Reformation morality plays, is dependent upon the audience understanding the truthfulness of Protestant theology and verses and also the deceptiveness and wickedness of Catholic theology, whose best example is the secular play of Calderón.

The Vices in post-Reformation morality plays are sometimes depicted as being Catholic. At times this depiction is achieved through their physical appearance. For example, Vices in post-Reformation morality plays could be dressed as cardinals, friars, monks, or the pope. Other times, the Vice comes out and states he is a Catholic, or elucidates that he is Catholic by swearing a Catholic pledge. To deceive the victim of post-Reformation morality plays, the Vice typically assumes a new name to disguise what actual Vice he is.

title: Morality play