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Stave church

A stave church is a medieval wooden Christian church building once common in north-western Europe. The name derives from the building's structure of post and lintel construction, a type of timber framing where the load-bearing ore-pine posts are called stafr in Old Norse (stav in modern Norwegian). Two related church building types also named for their structural elements, the post church and palisade church, are often called 'stave churches'.

Originally much more widespread, most of the surviving stave churches are in Norway. The only remaining medieval stave churches outside Norway are those of circa 1500 Hedared stave church in Sweden and one Norwegian stave church relocated in 1842 to contemporary Karpacz in the Karkonosze mountains of Poland. One other church, the Anglo-Saxon Greensted Church in England, exhibits many similarities with a stave church but is generally considered a palisade church.

Construction
Archaeological excavations have shown that stave churches are descended from palisade constructions and from later churches with earth-bound posts.

Similar palisade constructions are known from buildings from the Viking Age. Logs were split in two halves, set or rammed into the earth (generally called post in ground construction) and given a roof. This proved a simple but very strong form of construction. If set in gravel, the wall could last many decades, even centuries. An archaeological excavation in Lund uncovered the postholes of several such churches.

In post churches, the walls were supported by sills, leaving only the posts earth-bound. Such churches are easy to spot at archaeological sites as they leave very distinct holes where the posts were once placed. Occasionally some of the wood remains, making it possible to date the church more accurately using radiocarbon dating or dendrochronology. Under the Urnes Stave Church, remains of two such churches have been found, with Christian graves discovered beneath the oldest church structure.

A single church of palisade construction has been discovered under the Hemse stave church.

The next design phase resulted from the observation that earthbound posts were susceptible to humidity, causing them to rot away over time. To prevent this, the posts were placed on top of large stones, significantly increasing their lifespans. The stave church in Røldal is believed to be of this type.

In later churches the posts were set on a raised sill frame resting on stone foundations. This is the stave church in its most mature form.

It is now common to group the churches into two categories: the first, without free-standing posts, often referred to as Type A; and the second, with a raised roof and free-standing internal posts, usually called Type B.

Those with the raised roof, Type B, are often further divided into two subgroups. The first of these, the Kaupanger group, have a whole arcade row of posts and intermediate posts along the sides and details that mimic stone capitals. These churches give an impression of a basilica.

The other subgroup is the Borgund group. In these churches the posts are connected halfway up with one or two horizontal double ″pincer beams″ with semicircular indentations, clasping the row of posts from both sides. Cross-braces are inserted between the posts and the upper and lower pincer beams (or above the single pincer beam), forming a very rigid interconnection, and resembling the triforium of stone basilicas. This design made it possible to omit the freestanding lower part of intermediate posts. In some churches only the four corner posts remain (for example in Lomen Stave Church).

Many stave churches had or still have outer galleries or ambulatories around their whole perimeters, loosely connected to the plank walls. These probably served to protect the church from a harsh climate, and for processions.

Single-nave church, Type A
At the base of Type A churches, there are four heavy sill beams on a low foundation of stones. These are interconnected in the corner notch, forming a rigid sill frame. The corner posts or staves (stavene in Norwegian) are cross-cut at the lower end and fit over the corner notches and cover them, protecting them from moisture.

On top of the sill beam is a groove into which the lower ends of the wall planks (veggtilene) fit. The last wall plank is wedge-shaped and rammed into place. When the wall is filled in with planks, the frame is completed by a wall plate (stavlægje) with a groove on the bottom, holding the top ends of the wall planks. The whole structure consists of frames – a sill frame resting on the stone foundation, and the four wall frames made up of sills, corner posts and wall plate.

The wall plates support the roof trusses, consisting of a pair of principal rafters and an additional pair of intersecting "scissor rafters". For lateral bracing, additional wooden brackets (bueknær) are inserted between the rafters.

Every piece is locked into position by other pieces, making for a very rigid construction; yet all points otherwise susceptible to the harsh weather are covered.
 * The single-nave church has a square nave and a narrower square choir. This type of stave church was common at the beginning of the 12th century.
 * The long church (Langkyrkje), has a rectangular plan with nave and choir of the same width. The nave will usually take up two-thirds of the whole length. This type was common at the end of the 13th century.
 * The center-post church (Midtmastkyrkje), has a single central post reaching all the way up to and connected to the roof construction. But the roof is a simple hipped one, without the raised central part of the Type B churches. This variation on the common type of church, found in Numedal and Hallingdal, dates to around 1200.

Single-nave churches in Norway: Grip, Haltdalen, Undredal, Hedal, Reinli, Eidsborg, Rollag, Uvdal, Nore, Høyjord, Røldal, and Garmo. The only remaining church of this type outside Norway is the Hedared church in Sweden, which shows similarities with the church at Haltdalen.

Church with a raised roof, Type B
On the stone foundation, four huge ground beams (grunnstokker) are placed like a ⌗ sign, their ends protruding 1–2 meters from the lap joint where they intersect. The ends of these beams support the sills of the outer walls, forming a separate horizontal frame. The tall internal posts are placed on the internal frame of ground beams, and carry the main roof above the central nave (skip). On the outer frame of sills rest the main wall planks (veggtiler), carrying the roof over the pentice or aisles (omgang) surrounding the central space. The roof thus slopes down in two steps, as in a basilica.

The tall internal posts (staver) are interconnected with brackets (bueknær), and also connected to the outer walls with aisle rafters, creating a laterally rigid construction. Closer to the top of the posts (staver), shorter sills inserted between them support the upper wall (tilevegg). On top of the posts wall plates (stavlægjer) support the roof trusses, similar to those of the single-nave churches.

The Kaupanger group consists of: Kaupanger, Urnes, Hopperstad, and Lom. The Borgund group consists of: Borgund, Gol, Hegge, Høre, Lomen, Ringebu, and Øye.

This form of a church can also be recognized from the holes which remain from earlier earth-bound post churches built on the same sites. Little is known about what these older churches actually looked like or how they were constructed, as they were all destroyed or replaced many centuries ago.

Palisade work
The oldest technique is often called palisade work and was a self-supporting wall construction with densely placed earthen pillars or planks, which enclosed a room and at the same time carried the roof. Later, split logs were used, which gave the walls a flat inside, and the edges could be leveled or fitted with tongue and groove. Palisade churches have not been found in Norway.

To prevent early decay, the posts or planks were tarred, and the lower ends were charred by burning. The palisade rows were often placed in ditches filled with stone. It was long thought that this technique disappeared before the turn of the last millennium, but new research shows that it was in use right up to the beginning of the 12th century.

The only structure in this technique that has survived into our time is a wall in the middle section of Greensted Church in England. This led to this church being for a long time considered the oldest wooden structure in Europe. A common dating of the church was about the year 845, but modern dendrochronological dating estimates the church's year of construction to the period just after the year 1053 (+10 / −55 years).

The post technique
By lifting the pole planks up from the ground and placing them on sleepers clamped between more powerful corner or intermediate posts, the risk of rot damage was reduced. Thinner materials could then be used in the complementary parts of the construction. Earthen piles of coarse round timber could stand for a relatively long time before rotting. They may have been scorched at the lower end to avoid premature decay.

Postholes, often with remnants of the former pillars, have been found under or near several stave churches and in places where legends say that there must have been churches. Remains of approximately 25 pillar buildings have been identified in Norway, and indirect traces of 7–8 more. Remains of pillar churches are also found under stone churches such as Mære and Kinsarvik.

Many of the earliest churches in Norway were built using this technique, but no such buildings have survived. It is an open question whether limited life was the reason why they were replaced by real stave churches with sleepers, or whether there were other reasons. Some of the older materials found in several of the stave churches are thought to originate from such early pillar churches, in particular at the Urnes stave church in Luster, where many building parts with wooden sheds in the urn style must have belonged to an older church. It has now been proven that the reused building parts originally belonged to the current church's forerunner, dendrochronologically dated to the period 1070–1080. However, this was not a post church, but a real stave church where corner poles and wall planks stood on sleepers.

Håkon Christie assumed that the post construction fell out of use because the posts rotted from below. Jørgen H. Jensenius believes that archaeological material does not provide unequivocal support for Christie's hypothesis; a change in size or transition to a stone church may also explain why excavated pillars fell out of use. Røldal Stave Church may have had some pillars set in the ground until 1913. In Lom Stave Church, the stone foundations have been laid approximately directly over the refilled postholes. Apart from different foundation methods, Jensenius believes that the pillar churches were essentially similar to stave churches.

Stave work
Of buildings from the Middle Ages with standing timber in load-bearing structures, only the churches in the last developed method of construction, the stave, have been left standing in our time. By lifting the entire structure up on stone foundations and placing the poles on sleepers, the life of the structure was significantly extended. The technique was developed as early as the 11th century, but it has only been proven in the forerunner of the current stave church. This was also a real stave church, since both the corner stakes and the tiles have stood on sleepers that were reused as foundations for the existing church.

Stone as a base for poles was used as early as Roman times and additional walls in sleepers may have been used from the 400s and 600s.

Size
Lorentz Dietrichson believed that the stave churches were originally small and only later built with larger dimensions. He believed that the background for this was the construction technique. He points out that the youngest churches in the Mør type are the largest. He calculated the ground plan and area for 79 churches, and the nine largest were all in Sunnmøre with Hjørundfjord, Volda and Norddal of over 280 m2. This is three times larger than, for example, Urnes and Hopperstad. According to Dietrichson, the large size of the stave churches in Sunnmøre were partly a result of later expansions. He estimated the cross arms of Volda Stave Church at 7.3 × 6 meters. Hjørundfjord Stave Church was a "half-cross church" with only one cross arm measuring 7.9 × 9.1 meters. The first stave church had cross arms of 7.9 × 6.7 meters after expansion. Dietrichson was unsure whether the cross arms in the Møre churches were generally added in the lath construction or whether it was a medieval stave construction. He concluded that several were originally listed as cruciform churches in stakes, including Hareid, Volda, Vatne and Ørsta. For some other churches (Bremsnes and Kornstad on Nordmøre), contemporary sources say that the cross arms were later added to the lumber. According to Håkon Christie, these churches of the Mør type had a simpler construction and were both larger and longer than the other types. Roar Hauglid estimated that most (80–90%) of the medieval Norwegian stave churches were simple single-nave buildings (Type A) and most were relatively small. Hauglid called these "the ordinary Norwegian stave church".

History

Stave churches were once common in northern Europe. In Norway alone, it was thought about 1000 were built; recent research has increased this estimate and it is now believed there may have been closer to 2000.

Norway
Norwegian stave churches older than the 1100s are known only from written sources or from archaeological excavations, but written sources are sparse and difficult to interpret. Only 271 masonry churches were constructed in Norway during the same period, of which 160 still exist, while in Sweden and Denmark there were 900 and 1800 masonry churches respectively. Frostathing Law and Gulating law rules about "corner posts" show that the stave church was the standard church building in Norway, even though the Catholic church preferred stone. All wooden churches in Norway before the reformation were constructed with staves. Log building is younger than stave building in Norway, and was introduced in residential buildings around year 1000. Stave building is not influenced by the log technique. Only 29 stave churches have survived in Norway. Most of these were built between 1150 and 1350.

The word "stave church" is unknown in Old Norse, presumably because there were no other types of wooden churches. When Norway's churches after the Reformation were constructed from logs, there was a need for a separate term for the older churches. In written sources from the Middle Ages, there is a clear distinction between stafr (posts) and þili or vægþili (wall boards). However, in documents from the 1600–1700s, "stave" was also used for wall boards or panels. Emil Eckhoff in his Svenska stavkyrkor (1914–1916) also included wood-frame church buildings without posts.

According to Norway's oldest written laws and Old Norwegian Homily Book, the consecration of the church was valid as long as the four corner posts were standing. One of the sermons in the old homily book is known as the "stave church sermon". The sermon dates from around 1100 and was presumably performed at consecrations, or on their anniversaries. The sermon text is a theological interpretation of the building elements in the church. It names most of the building elements in the stave church, and can be a source of terminology and technique. For instance, the sermon says: "The four corner posts of the church are a symbol for the four gospels, because their teachings are the strongest supports within the whole of Christianity."

Church building was mentioned in the Gulatingsloven (Gulating Law), which was written down in the 1000s. In the chapter on Christianity, the 12th article states: "If one man builds a church, either lendmann does it or a farmer, or whoever builds a church, shall keep the church and the plot in good condition. But if the church breaks down and corner posts fall, then he shall bring timber to the plot before twelve months; if not, he will pay three marks in punishment to the bishop and bring timber and rebuild the church anyway.

(Um einskildmenn byggjer kyrkje, anten lendmann gjer det eller bonde, eller kven det er som byggjer kyrkje, skal han halda henne i stand og inkje øyda tufti. Men um kyrkja brotnar og hyrnestavane fell, då skal han føra timber på tufti innan tolv månadar; um det ikkje kjem, skal han bøta tre merker for det til biskopen og koma med timber og byggja opp kyrkja likevel.)"

In Norway, stave churches were gradually replaced; many survived until the 19th century when a substantial number were destroyed. Today, 28 historical stave churches remain standing in Norway. Stave churches were particularly common in less populated areas in high valleys and forest land, and in fishermen's villages on islands and minor villages along fjords. By about 1800, 322 stave churches were still known in Norway, most of them in sparsely populated areas. If the main church was masonry, the annex church could be a stave church. Masonry churches were mostly built in towns, along the coast, and in rich agricultural areas in Trøndelag and eastern Norway, as well as in the larger parishes in fjord districts in western Norway. No new churches were built in Norway during the 1400s and 1500s. Norway's stave churches largely disappeared until 1700 and were replaced by log buildings. Several stave churches were redesigned or enlarged using different techniques during 1600–1700; for instance, Flesberg Stave Church was converted into a cruciform church partly in log construction. According to Dietrichson, most stave churches were dismantled to make room for a new church, partly because the old church had become too small for the congregation, and partly because the stave church was in poor condition. Fire, storm, avalanche and decay were other reasons. In 1650 there were about 270 stave churches left in Norway, and in the next hundred years 136 of these disappeared. There were still 95 stave churches in 1800, while over 200 former stave churches were still known by name or in written sources. From 1850 to 1885, 32 stave churches disappeared; since then only the Fantoft Stave Church has been lost.

Heddal stave church was the first stave church described in a scholarly publication, when Johannes Flintoe wrote an essay in Samlinger til det Norske Folks Sprog og Historie (Christiania, 1834). The book also printed Flintoe's drawings of the facade, the ground floor and the floor plan – the first known architectural drawing of a stave church.

Between 1950 and 1970, postholes from older buildings were discovered under Lom stave church as well as under masonry churches such as Kinsarvik Church, and this discovery was an important contribution to understanding the origin of stave churches. Postholes were first identified during excavations in Urnes stave church.

Other countries
The number of stave churches constructed in Iceland and the rest of Europe is unknown. Some believe they were the first type of church to be constructed in Scandinavia; however, the post churches are an older type, although the difference between the two is slight. A stave church has a lower construction set on a frame, whereas a post church has earth-bound posts.

In Sweden, the stave churches were considered obsolete in the Middle Ages and were replaced. In Denmark, traces of post churches have been found at several locations, and there are also parts still in existence from some of them. A plank of one such church was found in Jutland. The plank is now on display at the National Museum of Denmark in Copenhagen and an attempt at reconstructing the church is a featured display at the Moesgård Museum near Aarhus. Marks created by several old post churches have also been found at the old stone church in Jelling.

In Sweden, the medieval Hedared stave church was constructed c. 1500 at the same location as a previous stave church. Other notable places are Maria Minor church in Lund, with its traces of a post church with palisades, and some old parts of Hemse stave church on Gotland. In Skåne alone there were around 300 such churches when Adam of Bremen visited Denmark in the first half of the 11th century, but how many of those were stave churches or post churches is unknown.

In England, there is one similar church of Saxon origin, with much debate as to whether it is a stave church or predates them. This is the Greensted Church in Essex. General consensus categorizes it as Saxon Type A. Another church bears similarities to stave churches, the medieval stone church of St. Mary in Kilpeck in Herefordshire. It features a number of dragon heads.

In Germany, there is one stone church with a motif depicting a dragon similar to those often seen on Norwegian stave churches and on surviving artifacts from Denmark and Gotland. Whether this decoration can be attributed to cultural similarities or whether it indicates similar construction methods in Germany has sparked controversy.

Replica stave churches have been built in several American communities, mostly in the Upper Midwest, with Norwegian or Islandic immigrant populations.

Influences
Lorentz Dietrichson in his book De norske Stavkirker ("The Norwegian Stave Churches") (1892) claimed that the stave church is "a brilliant translation of the Romanesque basilica from stone to wood" ("En genial oversettelse fra sten til tre av den romanske basilika"). Dietrichson claimed that Type B displays an influence from early Christian and Roman basilicas. The style was assumed to be transferred via Anglo-Saxon and Irish architecture, where only the particular roof construction was local. Dietrichson emphasized the clerestory, arcades and capitals. The "basilica theory" was introduced by N. Nicolaysen in Mindesmærker af Middelalderens Kunst i Norge (1854). Nicolaysen wrote: "Our stave churches are now the only remaining of its kind, and according to the sparse records and known circumstances, it appears that nothing similar existed except perhaps in Britain and Ireland." ("Vore stavkirker er nu de eneste i sit slags, og saavidt sparsomme beretninger og andre omstændigheder lader formode, synes de heller ikke tidligere at have havt noget sidestykke med undtagelse af maaske i Storbritannien og Irland.") Nicolaysen further claimed that the layout and design may have been inspired by Byzantine architecture. Nicolaysen wrote: "All facts suggest that the stave churches like the masonry churches and all medieval architecture in Western Europe originated from the Roman basilica." ("Alt synes at henpege paa, at forbilledet til vore stavkirker ligesom til stenkirkerne og overhovedet til hele den vesteuropæiske arkitektur i middelalderen er udgaaet fra den romerske basilika.") This theory was further developed by Anders Bugge and Roar Hauglid. Peter Anker believed that the influence from foreign masonry architecture was primarily in decorative details.

Per Jonas Nordhagen does not reject the basilica theory, but suggests development along two paths and that the basilical was a development towards larger and technically more sophisticated churches. The main, progressive path according to Nordhagen lead to Torpo and Borgund.

Folklore and circumstantial evidence seem to suggest that stave churches were built upon old indigenous Norse worship sites, the hof. Dietrichson believed that the stave churches were closely connected to the hof and the "hof theory" attracted interest in the 1930s and 1940s. The theory assumed that the hofs had a square, raised roof supported by four columns. During Christianization of Norway local chiefs were forced to either dismantle the hofs or to convert hofs into churches. Bugge and Norberg-Schultz accordingly claimed that "there is no reason to believe that the last hofs and the first churches had any major differences" ("og da er det liten grunn til å tro at de siste hov har skilt seg synderlig fra de første kirker"). This assumption has been rejected by archeological evidence several times, in the case of Iceland by Åge Roussel. Olaf Olsen described the hof merely as function related to ordinary buildings on major farms. If the hof was a particular building they remain to be identified, according to Olsen. Olsen rejected the hof theory. Nicolay Nicolaysen also concluded that there is not a single known case of a hof that was converted to a church.

Lack of historical evidence for hofs as buildings undermines the hof theory. Nicolaysen also introduced the community centre hypothesis which argued that hofs were destroyed and churches constructed on the same convenient location for the local community. Location near a previous hof would then be a coincidence, according to Nicolaysen. Pope Gregory I encouraged (year 601) Augustine of Canterbury to reuse pre-Christian temples, but this had little relevance for Norway according to Nicolaysen. Jan Brendalsmo in his dissertation concluded that churches were often established on major farms or farms of local chiefs and close to feasting halls or graveyards.

Stave churches sometimes appear to have built upon or used materials from old pagan worship sites and are considered to be the best evidence for the existence of Norse Pagan temples and the best guide as to what they looked like. The layout of the churches is believed to have mimicked old Pagan temples in design and was possibly designed in order to adhere to old Norse cosmological beliefs, especially as some churches were built around a central point like a world tree. Stave churches were also often located near or in the sight of large natural formations which also had a significant role in Norse Paganism, thus also suggesting a form of continuity through placement and symbolism. Furthermore, dragons' heads and other clear mythological symbolism suggests the cultural blending of Norse mythological beliefs and Christianity in a non-contradictory synthesis. Owing to this evidence newer research has suggested that Christianity was introduced into Norway much earlier than was previously assumed.

Church arsons and attempts

While church fires of wooden churches in Norway are relatively common, due to wood's flammable nature, from 1992 to 1995, the number rose dramatically. Between 1992 and 1996, there were at least 50 attacks on Christian churches in Norway, some of which were Stave churches. Members of the Norwegian black metal scene are thought to be largely responsible; in every arson case that was solved, those responsible were black metal fans.

The first church burned was Norway's Fantoft Stave Church, which was burnt to the ground in June 1992. Police believe Varg Vikernes of the metal band Burzum was responsible, and the cover of Burzum's EP Aske ("ashes") is a photograph of the destroyed church. On 16 May 1994, Vikernes was found guilty for burning down the Holmenkollen Chapel, Skjold Church, and Åsane Church. Those convicted for church burnings showed no remorse and described their actions as a symbolic "retaliation" against Christianity in Norway. Vikernes would come to be seen as "the perpetrator of a few and inspiration for many of the fires".

The following is a partial list of the church arsons:

1992 1993 1994 1995
 * 23 May: attempted burning of Storetveit Church in Bergen.
 * 6 June: burning of Fantoft stave church in Bergen – Varg Vikernes is strongly suspected as the culprit, but was not convicted.
 * 1 August: burning of Revheim Church in Stavanger.
 * 21 August: burning of Holmenkollen Chapel in Oslo – Varg Vikernes and Faust were convicted for this; Euronymous also participated, but was murdered in August 1993.
 * 1 September: burning of Ormøya Church in Oslo.
 * 13 September: burning of Skjold Church in Vindafjord – Varg Vikernes and Samoth were convicted for this.
 * 3 October: burning of Hauketo Church in Oslo.
 * 24 December: burning of Åsane Church in Bergen – Varg Vikernes and Jørn Inge Tunsberg were convicted for this.
 * 25 December: burning of a Methodist church in Sarpsborg – a firefighter was killed while fighting this fire.
 * 7 February: burning of Lundby New Church in Gothenburg, Sweden.
 * 13 March: burning of a church in Sund.
 * 27 March: burning of Seegård Church in Snertingdal.
 * 16 May: attempted burning of Gol stave church in Buskerud.
 * 17 May: attempted burning of Åmodt Chapel in Buskerud.
 * 4 June: burning of Frogn Church in Drøbak.
 * 19 June: attempted burning of Heni Church in Gjerdrum.
 * 7 July: burning of a church in Jeløy.
 * 21 July: attempted burning of Odda's Church.
 * 13 August: attempted burning of Loop Chapel in Meldal.
 * 10 December: attempted burning of Åkra Church.
 * 22 December: attempted burning of Askim Church.
 * 26 December: attempted burning of Klemestrud Church.
 * 13 May: burning of Lord Church in Telemark.
 * 25 May: burning of Såner Church in Vestby.
 * 14 June: burning of Moe Church in Sandefjord.
 * 21 July: attempted burning of a church college in Eidanger.
 * 3 September: attempted burning of Vågsbygd church college in Kristiansand.
 * 3 November: burning of Innset Church in Rennebu.

Architecture and decoration
Even though the wooden churches had structural differences, they give a recognizable general impression. Formal differences may hide common features of their planning, while apparently similar buildings may turn out to have their structural elements organized completely differently. Despite this, certain basic principles must have been common to all types of building.

Basic geometrical figures, numbers that were easy to work with, one or just a few length units and simple ratios, and perhaps proportions, were among the theoretical aids all builders inherited. The specialist was the man who knew a particular type of building so well that he could systematise its elements in a slightly different way from previous building designs, thus carrying developments a stage further.

"Exposing the timber frame on the interior and/or exterior of the structures is seen to release its matrix of timber members and its capacity to contribute architectural expression to buildings. The matrix, forming ‘lines’ in space, has an expressive potential that includes the capacity to delineate proportion, direct eye-movement, suggest spatial enclosure, create patterning, permit transparency and establish continuity with landscape."

Portals
Portals or parts of the portals from about 140 stave churches have been preserved. There are roughly three portal types: the simple profile portal, the column portal and the beam portal.

The simple profile portal is a doorway framed by simple profiles or pilasters. These portals are mostly used on cord doors. About 20 such doors have been preserved.

The column portal is derived from stone architecture. It has full or half columns that carry a curved archivolt. The columns have bases and chapters. They are richly decorated and were used both on front doors and inside cross-sections. About 40 such portals are known.

The beam (or magnificent) portal consists of two portal planks and a top piece with continuous decoration. The upper part has two to five horizontal planks that are folded into each other with tongue and groove. This is supported by the standing wall planks that flank the doorway. 75 more or less complete portals of this type have been preserved. In some beam portals, the column motif is also incorporated together with the surface decorations, with or without archivolt.

Most of the preserved material comes from Sogn-Hardanger and from the mountain villages in eastern Norway. The main part of the portals is Romanesque and lacks Gothic features.

It is possible that the portals may have been painted, but this has been difficult to determine with certainty. The paint on the few that are painted today seems to be newer.

It is common to divide the portals according to style to Urnes style and Romanesque style.

Iconography
Most portals show dragons, "lions" and vines that do not refer to specific biblical or other Christian stories. One of the exceptions is the Christian motifs found on the west portal from the torn Hemsedal stave church, which shows St. Olav's martyrdom and status as a Christlike saint.

A research problem has been the portal's iconography. As for the Urnes style portals, the idea that it should have a pagan content is rejected. The large animal has been interpreted as a lion. The lion can represent Christ who fights with and wins over evil.

Common features of most portals are that they are monumental and that they have fighting dragons, which may be symbolic of magic to avert pain. Bugge believes that this may be a pagan iconography in Christian interpretation. In the Sogn-Valdres portals the lion is replaced by a vine, which also represents Christianity. in reference to Joh. 15.5: "I am the vine, you are the branches." Hohler opposes this interpretation. She believes that the portals cannot have a religious content, but is a picture of the client's or builder's intention, a ruling motif. There are many portals in Europe that are pure ornaments. She refers to Bernhard of Clairvaux, who opposed the use of animals in the Christian context.

"What justification do the beasts of the monastery have for the formless treasure of form and the formless formlessness? What do pictures there have to do with unclean monkeys, wild lions, amazing centaurs and half-humans? Why serve tigers, fighting knights, hunters who blow their horns? There you see under a head several bodies, and there you see on a four-legged body a snake's tail, there on a fish an animal head – Everywhere there is such a rich and fantastic collection of different shapes that one directs one's eyes to the sculptures rather than the content of the holy books." She therefore believes that animal motifs in Romanesque art have little religious significance, and the portals can be pure ruler symbols.

Hoftun believes that many of the so-called pagan portal motifs have a clear Christian message, believing that in principle the Norwegian stave church motifs do not differ from many of the motifs found in other Romanesque church art, such as on Romanesque church portals and stone baptismal fonts in Sweden and Denmark.

Other researchers believe that the portals are inspired by English art. The background may be manuscripts and stone sculpture. Some of these manuscripts are animal books with a Christian allegorical content, often referred to as bestiaries. The origin of these is the Physiologus, a collection of allegories about animals with Christian interpretations, which are said to have originated in Alexandria in the 2nd century. This basic text was in Greek, and throughout the Middle Ages the text was translated into a number of languages. These stories are also the background for all the bestiaries that are preserved in various libraries and collections. The sources of the Physiologus are Indian, Hebrew and Egyptian animal stories and various classical texts written by, among others, Aristotle and Pliny the Elder. No early Greek text has survived; the oldest preserved are in Latin, but these must be very close to the Greek original. Gradually, it became common to illustrate the texts, but there is a leap in development, and a number of texts with illustrations have been lost.

Lindkvist refers to the Physiologus as a background for animal depictions in portals on Gotland. These stone churches were often built after the stave churches in the same places had become too small. Unfortunately, most of the wooden churches have disappeared, so it is not possible to study the decor. But it is not unreasonable to assume that they have had the same decor as Norwegian stave churches, and that these motifs may then have been continued in the stone portals. Background and origin would then be approximately the same.

Dating of churches
Stave churches can be dated in various ways: by historical records or inscriptions, by stylistic means using construction details or ornaments, or by dendrochronology and radiocarbon dating. Often historical records or inscriptions will point to a year when the church is known to have existed. Archaeological excavations can yield finds that provide relative dating for the structure, whereas absolute dating methods such as radiocarbon dating and dendrochronology can provide a more exact date. One drawback of dendrochronology is that it tends to overlook the possibility that the wood could have been reused from an older structure, or felled and left for many years before use.

An important problem in dating the churches is that the solid ground sills are the construction elements most likely to have the outer parts of the log still preserved. Yet they are the most susceptible to humidity, and as people back then reused building parts, the church may have been rebuilt several times. If so, a dendrochronological dating may be based upon a log from a later reconstruction.

Coin finds made under the church floors are also important for dating.

Results from studies with the photodendrome method published in 2019 have come with adjusted estimates for age of the timber used. The churches at Urnes, Kaupanger and Hopperstad were examined particularly thoroughly.
 * Hoppestad Stave Church dendrodated to 1131–1132, previously assumed 1125–1250.
 * Kaupanger Stave Church dated to 1137–1138, formerly adopted 1170–1200.
 * Gol Stave Church 1204–05, previously assumed 1170–1309.
 * Borgund Stave Church 1180–1181, previously assumed 1150–1250.
 * Kvernes Stave Church, 1633, previously believed to be from the Middle Ages, is the only known stave church in Norway built after the Reformation.

Stave Churches Program
The poor condition of the stave churches led the National Heritage Board to start the Stave Churches Program in 2001. The program was to create positive ripple effects in the form of greater local activity with traditional ways of using materials and resources.

The goals of the program were:
 * to restore the stave churches so that they can be preserved for posterity,
 * to preserve the decor and church art,
 * to supplement the documentation of the stave churches as a basis for research and reconstruction of lost parts.

The results of the program with the details of what has been done at the individual churches was documented in a report in 2008.

List of stave churches
Most stave churches are in Norway, but they can also be found in Iceland, Sweden, Denmark, and Germany. Stave churches are quite popular phenomenon and several have been built or rebuilt around the world. The two most copied are Borgund and Hedared, with some variations, and sometimes with adaptations to add elements from known stave churches from the area. In other places they are of a freer form and built for display.

Norway

 * Borgund Stave Church, Sogn og Fjordane – end of the 12th century.
 * Eidsborg Stave Church, Telemark – middle of the 13th century.
 * Flesberg Stave Church in Flesberg, Buskerud – c. 1200.
 * Garmo Stave Church, Oppland – c. 1150.
 * Gol Stave Church in Gol (now at Norwegian Museum of Cultural History, Oslo), Buskerud – 1212.
 * Grip Stave Church, Møre og Romsdal – second half of the 15th century.
 * Haltdalen Stave Church, Sør-Trøndelag – 1170–1179.
 * Hedal Stave Church, Oppland – second half of the 12th century.
 * Heddal Stave Church, Telemark – beginning of the 13th century.
 * Hegge Stave Church, Oppland – 1216.
 * Hopperstad Stave Church, Sogn og Fjordane – 1140.
 * Høre Stave Church, Oppland – 1179.
 * Høyjord Stave Church, Andebu, Vestfold – second half of the 12th century.
 * Kaupanger Stave Church, Sogn og Fjordane – 1190.
 * Kvernes Stave Church, Møre og Romsdal – second half of the 14th century.
 * Lomen Stave Church, Oppland – 1179.
 * Lom Stave Church, Oppland – 1158.
 * Nore Stave Church, Nore og Uvdal, Buskerud – 1167.
 * Øye Stave Church, Oppland – second half of the 12th century.
 * Reinli Stave Church, Oppland – 1190.
 * Ringebu Stave Church, Oppland – first quarter of the 13th century.
 * Rollag Stave Church, Rollag, Buskerud – second half of the 12th century.
 * Rødven Stave Church, Møre og Romsdal – c. 1200.
 * Røldal Stave Church, Hordaland – first half of the 13th century (could be a post church).
 * Torpo Stave Church, Ål, Buskerud – 1192.
 * Undredal Stave Church, Sogn og Fjordane – middle of the 12th century.
 * Urnes Stave Church, Sogn og Fjordane – first half of the 12th century (on UNESCO’s World Heritage Site).
 * Uvdal Stave Church, Uvdal, Buskerud – 1168.

Outside Norway

 * Vang Stave Church, moved from Norway to Poland in 1842.
 * Hedared stave church, Sweden, c. 1500, built on the site of an earlier stave church.
 * Greensted Church, England, 845 or 1053, the only one palisade church is known to survive, has been claimed to be the oldest wooden church in the world, and probably the oldest wooden building in Europe still standing.

Notable replicas and later built churches

 * Skaga stave church in Töreboda, Västra Götaland county, Sweden, built in the 12th century, torn down in the 19th century, rebuilt in the 1950s, burnt down, and rebuilt again in 2001.
 * Heimaey stave church at Heimaey, Vestmannaeyjar, Iceland, built in 2000.
 * Chapel in the Hills in Rapid City, South Dakota, United States, a replica of Borgund Stave Church, 1969.
 * Little Norway, Wisconsin, United States, relocated to Orkdal, Norway, in 2016.
 * Fantoft Stave Church, Norway, built c. 1150, destroyed by arson in 1992 and rebuilt in 1997.
 * Fåvang Stave Church in Ringebu, Oppland, Norway, rebuilt in 1630 (two old churches rebuilt as one).
 * Hjemkomst Center in Moorhead, Minnesota, United States, Hopperstad replica built in 1998.
 * Washington Island Stavkirke on Washington Island, Wisconsin. Its design is based on the Borgund Stave Church, and was built between 1983 and 1995.

title: Stave church


text:
Marquess of Dorset

The title Marquess of Dorset has been created three times in the Peerage of England. It was first created in 1397 for John Beaufort, 1st Earl of Somerset, but he lost the title two years later. It was then created in 1442 for Edmund Beaufort, 1st Earl of Dorset, who was created Duke of Somerset in 1448. That creation was attainted in 1463.

It was created a third time in 1475 for Thomas Grey, 1st Earl of Huntingdon, who then resigned the earldom. The Marquess held the subsidiary title of Baron Ferrers of Groby (1299). The third marquess was created Duke of Suffolk in 1551, but he was attainted in 1554 and all the peerages were forfeited.

Marquesses of Dorset, first Creation (1397)

 * Other titles: Marquess of Somerset (1397) and Earl of Somerset (1397)

 * John Beaufort, 1st Marquess of Dorset (died 1410), eldest legitimated child of John of Gaunt, 1st Duke of Lancaster, himself third surviving son of Edward III was degraded in 1399 by Henry IV Bolingbroke for his role as a counter-appellant for Richard II

Marquesses of Dorset, second Creation (1443)

 * see Duke of Somerset, second Creation

Marquesses of Dorset, third Creation (1475)

 * Other titles: Baron Ferrers of Groby (1299)

 * Thomas Grey, 1st Marquess of Dorset (1451–1501) was stepson to Edward IV
 * Thomas Grey, 2nd Marquess of Dorset (1477–1530), a son of the 1st Marquess
 * Henry Grey, 3rd Marquess of Dorset, 1st Duke of Suffolk (1517–1554), eldest son of the 2nd Marquess, was created Duke of Suffolk in 1551. He was found guilty of treason, attainted and all of his honours forfeit in 1554.

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

title: Marquess of Dorset


text:
Masahide Ōta

Masahide Ōta (大田 昌秀) was a Japanese academic and politician who served as the governor of Okinawa Prefecture from 1990 until 1998. After starting his career as a professor at the University of the Ryūkyūs, he wrote books in English and Japanese, mostly about the Battle of Okinawa and Japan–United States bilateral relations following World War II. After his retirement as professor he was elected as governor and was best known for his strong stand against occupation of prefectural lands by military bases of United States, going against the Japanese central government at the time.

Early life and academic career
Ōta was born on 12 June 1925 on Kumejima Island, Okinawa and his family migrated during World War II. He became a student at the Okinawa Teacher's College, and during the Battle of Okinawa he was drafted into the Japanese Army's "Iron and Blood Student Corps"; he saw intense combat and many of his classmates died. After the end of the battle, he spent some months in hiding before emerging to surrender. He was educated at the Waseda University, Tokyo earning a bachelor's degree in English and took a master's degree in journalism from Syracuse University, New York.

From 1958, he was a professor at the University of the Ryūkyūs where he was chairman of Department of Social Science, and later dean of the College of Law and Letters. He published around 45 books in English and Japanese. His books were mostly based on Okinawa's role in Japan–United States relations, post-war occupation by the military in prefectures and the Battle of Okinawa of 1945.

Political career
In March 1990, Ōta retired from the university and in November of the same year was elected governor of Okinawa prefecture on a non-party platform defeating the 12-year sitting governor Junji Nishime. His campaign was based on removing U.S. bases from the island to bring back peace. He also opposed the then proposed bill to provide Japanese troops for United Nations' peacekeeping missions. He had a distinguished record as a governor, outspokenly arguing for the interests of the Okinawan people against both the United States military establishment in the Ryukyu Islands and the Japanese central government. After being elected as governor. Ōta failed to make headway on his campaign promises. His requests to discuss the issue of U.S. military occupation in the prefecture with the U.S. authorities were dismissed, stating that all such discussions would happen with the Japanese central government. In 1991, he reluctantly signed lease agreements that enabled military bases use of private lands. This resulted in disapproval from anti-war masses that had earlier supported Ōta in elections.

In February 1995, reports from Washington prepared by Harvard professor Joseph Nye indicated their plans of deploying over 100,000 soldiers in Japan and South Korea. On 4 September 1995, a 12-year-old local girl was raped by three U.S. servicemen, and protests were held against the military's establishments in the area. Ōta considered these two events as hindrance to peace in the prefecture. From 1996 to 1998, he actively worked to establish cordial relations with U.S. On 8 September 1996, he organized a plebiscite in his prefecture which brought results that about 60 percent of citizens who supported reduction of military bases. On 10 July 1996, he appealed to the Supreme Court of Japan to relocate various military bases to mainland. As governor, he rejected permissions of U.S. military asking to extend lease for use of private land. This led to conflict between local and central government. The central government amended laws which gave it the power to endorse such documents.

Due to Ōta's efforts, mass campaigns such as the Okinawa Women Act against Military Violence, which arranged a rally at Ginowan's Seaside Front on 21 October 1995, had nearly 85,000 people participating. The Japanese and American governments together set up the Special Action Committee on Okinawa (SACO) to deal with the problems. In 1996, the U.S. and Japanese government agreed to closure or relocation of various military bases, including the Marine Corps Air Station Futenma, the most prominent based in the centre of Ginowan city's residential area. The move has however not happened as in June 2017 due to various issues. In 1995, he inaugurated the monument Cornerstone of Peace which commemorated more than 200,000 people who died in the Okinawa Battle, including U.S. soldiers.

In 1998, Keizō Obuchi replaced Ryutaro Hashimoto as the Prime Minister of Japan. Obuchi supported the Liberal Democratic Party (LDP) candidate Keiichi Inamine for the governor's post in opposition to Ōta. By then the central and American government considered Ōta as "one of the biggest thornes" on both sides in the Japan–America relationship. Inamine, the eldest son of oil company Ryukyu Sekiyo's owner Ichiro Inamine, led a successful campaign not disregarding Ōta's work directly but calling it unrealistic. The central government cut down subsidies to Okinawa in 1998 leading to 9.2 percent of unemployment in August 1998. Inamine promised to revive the employment condition with his contacts in the central government and on the day of election LDP's campaign banners had slogan "9.2 percent" whereas Ōta campaigned using "Okinawans, Don't Sell Your Souls." Ōta lost with 46.9 percent votes whereas 52.1 percent went to Inamine.

In 2001, on the ticket of Social Democratic Party of Japan (SDPJ), Ōta won a seat in the House of Councillors (Upper House). He took retirement from active politics in 2007.

Later life and death
In 2013, he founded the Okinawa International Peace Research Institute at Naha. In April 2017, Ōta was reported to have been nominated for the Nobel Peace Prize.

Ōta died on his 92nd birthday on 12 June 2017 at a hospital in Naha after suffering from pneumonia and respiratory failure. Upon his death, Japanese Chief Cabinet Secretary Yoshihide Suga called him "an individual who energetically tackled Okinawa's base issues and (economic) development at a turbulent time."

Books

 * The Battle of Okinawa: The Typhoon of Steel and Bombs, Kume Publishing Company (1984) ISBN 9784906034116
 * Okinawa no minshū ishiki (shinpan), Shinsensha (1995)
 * Okinawa no teiō, kōtō benmukan, Asahi Shinbunsha (1996)

title: Masahide Ōta


text:
Duke of Dorset

Duke of Dorset was a title in the Peerage of Great Britain. It was created in 1720 for the politician Lionel Sackville, 7th Earl of Dorset.

History
The Sackville family descended from Sir Richard Sackville. His only surviving son, Thomas Sackville, was a statesman, poet and dramatist and notably served as Lord High Treasurer between 1599 and 1608. He was raised to the Peerage of England as Baron Buckhurst, of Buckhurst in the County of Sussex, in 1567, and was made Earl of Dorset in 1604, also in the Peerage of England. The titles descended in the direct line until the death of his grandson, the third Earl, in 1624. The late Earl was succeeded by his younger brother, the fourth Earl. He was Lord Chamberlain between 1642 and 1649. He was succeeded by his son, the fifth Earl. He married Lady Frances, daughter of Lionel Cranfield, 1st Earl of Middlesex. He was succeeded by his eldest son, the sixth Earl. He succeeded to the Cranfield estates on the death of his maternal uncle Lionel Cranfield, 3rd Earl of Middlesex. In 1675, two years before he succeeded his father, he was raised to the Peerage of England in his own right as Baron Cranfield, of Cranfield in the County of Dorset, and Earl of Middlesex. He was succeeded by his son, the aforementioned seventh Earl, who was made Duke of Dorset in 1720.

The Duke of Dorset was succeeded by his eldest son, the second Duke. The latter was succeeded by his nephew, the third Duke. He was the son of Lord John Sackville, second son of the first Duke. He was the British Ambassador to France between 1783 and 1789 in the lead-up to the French Revolution. He was succeeded by his only son, the fourth Duke. He died unmarried at an early age in 1815 after a fall from his horse. The titles passed to his cousin, Charles Sackville-Germain, 2nd Viscount Sackville, who became the fifth Duke. He was the son of George Germain, 1st Viscount Sackville, the third son of the first Duke (see Viscount Sackville). All titles became extinct on his death in 1843, though the baronies were later revived.

The family seat was Knole House, Kent, and the Sackvilles previously owned Buckhurst Park and Croxall Hall. On the death of the fourth Duke in 1815, Knole House was inherited by the late Duke's sister, Lady Elizabeth Sackville. She was the wife of George West, 5th Earl De La Warr, who assumed the additional surname of Sackville.

In 1865, the barony of Buckhurst held by the Earls and Dukes of Dorset was revived in Elizabeth's favour. In 1876 the Sackville title was also revived when her younger son Mortimer Sackville-West was created Baron Sackville.

Earls of Dorset (1604)

 * 1604–1608: Thomas Sackville, 1st Earl of Dorset (1536–1608)
 * 1608–1609: Robert Sackville, 2nd Earl of Dorset (1561–1609)
 * 1609–1624: Richard Sackville, 3rd Earl of Dorset (1589–1624)
 * 1624–1652: Edward Sackville, 4th Earl of Dorset (1591–1652)
 * 1652–1677: Richard Sackville, 5th Earl of Dorset (1622–1677)
 * 1677–1706: Charles Sackville, 6th Earl of Dorset (1643–1706)
 * 1706–1765: Lionel Cranfield Sackville, 7th Earl of Dorset (1688–1765) (created Duke of Dorset in 1720)

Dukes of Dorset (1720)

 * Lionel Cranfield Sackville, 1st Duke of Dorset (1688–1765)
 * Charles Sackville, 2nd Duke of Dorset (1711–1769)
 * John Frederick Sackville, 3rd Duke of Dorset (1745–1799)
 * George John Frederick Sackville, 4th Duke of Dorset (1793–1815)
 * Charles Sackville-Germain, 5th Duke of Dorset (1767–1843)

In fiction
The plot line of David Gurr's thriller A Woman Called Scylla assumes fictionally that the Dukedom of Dorset did not become extinct but survived into the 20th century. In 1977, the book's protagonist is the granddaughter of George Frederick Henry, the 10th Duke of Dorset. He is mentioned as being born in 1886, having been severely wounded at the Battle of Ypres in World War I and later devoting himself to gardening. Other members of the Duke's family also have a big share in the plot, particularly his daughter Mary, an SOE agent in World War II captured and tortured to death by the Nazis. Another fictional 20th-century Duke of Dorset is one of the title character's suitors in Zuleika Dobson.

title: Duke of Dorset


text:
Human interface device

A human interface device or HID is a type of computer device usually used by humans that takes input from or provides output to humans.

The term "HID" most commonly refers to the USB HID specification. The term was coined by Mike Van Flandern of Microsoft when he proposed that the USB committee create a Human Input Device class working group. The working group was renamed as the Human Interface Device class at the suggestion of Tom Schmidt of DEC because the proposed standard supported bi-directional communication.

HID standard
The HID standard was adopted primarily to enable innovation in PC input devices and to simplify the process of installing such devices. Prior to the introduction of the HID concept, devices usually conformed to strictly defined protocols for mouse, keyboards and joysticks; for example, the standard mouse protocol at the time supported relative X- and Y-axis data and binary input for up to two buttons, with no legacy support. All hardware innovations necessitated either overloading the use of data in an existing protocol or the creation of custom device drivers and the evangelization of a new protocol to developers. By contrast, all HID-defined devices deliver self-describing packages that may contain any number of data types and formats. A single HID driver on a computer parses data and enables dynamic association of data I/O with application functionality, which has enabled rapid innovation and development, and prolific diversification of new human-interface devices.

A working committee with representatives from several prominent companies developed the HID standard. The list of participants appears in the "Device Class Definition for Human Interface Devices (HID)" document. The concept of a self-describing extensible protocol initially came from Mike Van Flandern and Manolito Adan while working on a project named "Raptor" at Microsoft, and independently from Steve McGowan, who worked on a "SIM" project that defined a device protocol for the VFX1 VR Headset and its peripherals based on ACCESS.bus while at Forte Technologies. SIM was also self-describing and extensible, however it was more focused on SIMulation devices used for VR and motion capture. After comparing notes at a Consumer Game Developer Conference, Steve and Mike agreed to collaborate on a new standard for the emerging Universal Serial Bus (USB).

Prior to HID (c.1995), proprietary drivers needed to be installed for almost every device attached to a PC. This meant that device vendors needed to track OS releases, and regularly offer updated drivers for their devices, and to develop drivers for each OS that they wanted to support. Also, at the time any novel devices, e.g., Joysticks designed for flight simulators with extra buttons or D-pads, required software support not only by the driver, but by each game that supported them to enable new controls. This meant that the device developers had the additional responsibility of enabling each game that they wanted to support. The ability for a HID device to describe itself via a Report Descriptor, decoupled hardware device developers from game developers. The Report Descriptor concept also meant that OS vendors could write a HID driver (Parser) that could accommodate almost any HID device a vendor could dream up, without the vendor needing to write or maintain a driver for every OS that they wanted to support.

So the HID class decoupled device vendors from game and OS vendors, enabling device vendors to innovate faster, and reducing their development costs (e.g., no drivers or game developer support). The HID Usage Table document defines thousands of controls that can be presented by HID devices. Game vendors can query the OS's HID parser to identify the set of controls that are presented by a device, then map those controls to features in their game. Since its original release, the HID Usage Table (HUT) document has had hundreds of new uses added to it.

The HID protocol has its limitations, but all modern mainstream operating systems will recognize standard USB HID devices, such as keyboards and mice, without needing a specialized driver. However its versatility has been demonstrated by the fact that it has not been updated in over 22 years, and it is still supported by every PC, tablet and cell phone in production today. USB, hence HID, devices can be hot-plugged, so when installed, a message saying that "A 'HID-compliant device' has been recognized" generally appears on screen. In comparison, this message did not usually appear for devices connected via the PS/2 6-pin DIN connectors which preceded USB. PS/2 did not typically support plug-and-play, which means that connecting a PS/2 keyboard or mouse with the computer powered on does not always work and may pose a hazard to the computer's motherboard. Likewise, the PS/2 standard did not support the HID protocol. The USB human interface device class describes a USB HID.

The HID protocol (Report Descriptor and Report mechanism) has been implemented on many buses other than USB, including Bluetooth and I2C.

There are also a number of extensions to HID defined in "HID Integrated Usage Table Documents", including uninterruptible power supplies, video monitor controls, point of sale devices, arcade and gaming (slot machines) devices.

Report Descriptor
The Report Descriptor exposes the messages that are generated or accepted by a HID device. Each message is referred to as a 'Report'. Reports can define bits/controls in a device that can be read or written, or generated periodically to keep a host updated on the current status of the device. For instance, a mouse typically generates a Report 200 times a second to inform the host of any movement or button presses. Report Descriptors are 'bit orientated', meaning that controls can present between 1 and 32 bits of information. Each control defined in a Report Descriptor has an ID and defines its size and position in its Report. A Report Descriptor can define many Reports, each reporting a different set, or combination of information.

For example, a basic mouse defines a 3 byte Report where the least significant (0) bit of the report is the left button, the next (1) bit is the middle button, and the third (2) bit is the right button. To allow the mouse 8-bit X and Y position coordinates to conveniently land on byte boundaries, a 5-bit 'pad' is defined. Then the X coordinate is defined as an 8-bit relative value (i.e., number of 'mickeys' since the previous report) that resides in bit positions 8 through 15, and the Y coordinate is defined as an 8-bit relative value that resides in bit positions 16 through 24, resulting in a data packet that is presented to the host.

A Report Descriptor is extremely versatile, allowing a device to specify the resolution, range, and many other characteristics of each control that it presents. Being designed at a time when a mouse or keyboard controller was lucky to have 1KB of ROM for all its code and data, the Report Descriptor syntax has many features that allow its size to be minimized e.g., selected control parameters can persist across control multiple definitions, only needing to be redeclared if their value changes. The reports generated by a basic mouse can be described in 50 bytes, and a 104 keyboard in 65 bytes.

Physical Descriptor
A little known or understood feature of HID is the Physical Descriptor. The Physical Descriptor is used to define the parts of the human body that interact with the individual controls defined in the Report Descriptor. When controlling a game, the index finger and thumb are usually used to invoke repetitive actions. Because these fingers are considered to have the fastest 'twitch' response, they are typically used for pulling the trigger of a gun, or activating an often used game function. The Physical Descriptor allows a device vendor identify that which fingers rests on each control and prioritize the set of controls that can be reached by an individual finger. This feature enables a game vendor to intelligently present the best default button mapping, even for a device that didn't exist when the game was developed. The Physical Descriptor also enables full body motion capture information to be presented by a HID device, i.e., the angle, orientation, relative or absolute position of any joint in the human body. And through the Report Descriptor, the motion capture data can be presented at whatever resolution that the device can support.

Components of the HID protocol
In the HID protocol, there are 2 entities: the "host" and the "device". The device is the entity that directly interacts with a human, such as a keyboard or mouse. The host communicates with the device and receives input data from the device on actions performed by the human. Output data flows from the host to the device and then to the human. The most common example of a host is a PC but some cell phones and PDAs also can be hosts.

The HID protocol makes implementation of devices very simple. Devices define their data packets and then present a "HID descriptor" to the host. The HID descriptor is a hard coded array of bytes that describes the device's data packets. This includes: how many packets the device supports, the size of the packets, and the purpose of each byte and bit in the packet. For example, a keyboard with a calculator program button can tell the host that the button's pressed/released state is stored as the 2nd bit in the 6th byte in data packet number 4 (note: these locations are only illustrative and are device-specific). The device typically stores the HID descriptor in ROM and does not need to intrinsically understand or parse the HID descriptor. Some mouse and keyboard hardware in the market today is implemented using only an 8-bit CPU.

The host is expected to be a more complex entity than the device. The host needs to retrieve the HID descriptor from the device and parse it before it can fully communicate with the device. Parsing the HID descriptor can be complicated. Multiple operating systems were known to have shipped bugs in the device drivers responsible for parsing the HID descriptors years after the device drivers were originally released to the public. However, this complexity is the reason why rapid innovation with HID devices is possible.

The above mechanism describes what is known as HID "report protocol". Because it was understood that not all hosts would be capable of parsing HID descriptors, HID also defines "boot protocol". In boot protocol, only specific devices are supported with only specific features because fixed data packet formats are used. The HID descriptor is not used in this mode so innovation is limited. However, the benefit is that minimal functionality is still possible on hosts that otherwise would be unable to support HID. The only devices supported in boot protocol are One common usage of boot mode is during the first moments of a computer's boot up sequence. Directly configuring a computer's BIOS is often done using only boot mode. Sometimes a message will appear informing the user that the device has installed the correct driver and is now usable.
 * Keyboard – Any of the first 256 key codes ("Usages") defined in the HID Usage Tables, Usage Page 7 can be reported by a keyboard using the boot protocol, but most systems only handle a subset of these keys. Most systems support all 104 keys on the IBM AT-101 layout, plus the three extra keys designed for Microsoft Windows 95 (the left and right Windows key, and the Menu key).  Many systems also support additional keys on basic western European 105-, Korean 106-, Brazilian ABNT 107- and Japanese DOS/V 109-key layouts. Buttons, knobs and keys that are not reported on Usage Page 7 are not available.  For example, a particular US keyboard's QWERTY keys will function but the Calculator and Logoff keys will not because they are defined on Usage Page 12 and cannot be reported in boot protocol.
 * Mouse – Only the X-axis, Y-axis, and the first 3 buttons will be available. Any additional features on the mouse will not function.

Definition of a device
According to the HID specification, a device is described, during the report mode, as a set of controls or group of controls. Controls are matched by a field containing the data, and another containing a usage tag. Each usage tag is described in the spec as the constructor suggested use of the data described in the report mode.

The is a Windows app that can be used to generate all the descriptors associated with a HID device (see link below). It performs syntax checking, and can generate C, C Header and binary files for the HID descriptors. Its text-based Usage Table definion files can also be easily extended to define proprietary Usages (control types) or Usage Tables (the set of Usages associated with a device or feature).

Other protocols using HID
Since HID's original definition over USB, HID is now also used in other computer communication buses. This enables HID devices that traditionally were only found on USB to also be used on alternative buses. This is done since existing support for USB HID devices can typically be adapted much faster than having to invent an entirely new protocol to support mouse, touchpad, keyboards, and the like. Known buses that use HID are:
 * Bluetooth HID – Used for mouse and keyboards that are connected via Bluetooth
 * Serial HID – Used in Microsoft's Windows Media Center PC remote control receivers.
 * Zigbee input device – Zigbee (RF4CE) supports HID devices through the Zigbee input device profile.
 * HID over I²C – Used for embedded devices in Microsoft Windows 8
 * HID over SPI – Developed by Microsoft for faster, lower latency fixed-device communications
 * HOGP (HID over GATT) – Used for HID devices connected using Bluetooth Low Energy technology

title: Human interface device