text:
Euclidean minimum spanning tree

A Euclidean minimum spanning tree of a finite set of points in the Euclidean plane or higher-dimensional Euclidean space connects the points by a system of line segments with the points as endpoints, minimizing the total length of the segments. In it, any two points can reach each other along a path through the line segments. It can be found as the minimum spanning tree of a complete graph with the points as vertices and the Euclidean distances between points as edge weights.

The edges of the minimum spanning tree meet at angles of at least 60°, at most six to a vertex. In higher dimensions, the number of edges per vertex is bounded by the kissing number of tangent unit spheres. The total length of the edges, for points in a unit square, is at most proportional to the square root of the number of points. Each edge lies in an empty region of the plane, and these regions can be used to prove that the Euclidean minimum spanning tree is a subgraph of other geometric graphs including the relative neighborhood graph and Delaunay triangulation. By constructing the Delaunay triangulation and then applying a graph minimum spanning tree algorithm, the minimum spanning tree of $$n$$ given planar points may be found in time $$O(n\log n)$$, as expressed in big O notation. This is optimal in some models of computation, although faster randomized algorithms exist for points with integer coordinates. For points in higher dimensions, finding an optimal algorithm remains an open problem.

Definition and related problems
A Euclidean minimum spanning tree, for a set of $$n$$ points in the Euclidean plane or Euclidean space, is a system of line segments, having only the given points as their endpoints, whose union includes all of the points in a connected set, and which has the minimum possible total length of any such system. Such a network cannot contain a polygonal ring of segments; if one existed, the network could be shortened by removing an edge of the polygon. Therefore, the minimum-length network forms a tree. This observation leads to the equivalent definition that a Euclidean minimum spanning tree is a tree of line segments between pairs of the given points, of minimum total length. The same tree may also be described as a minimum spanning tree of a weighted complete graph, having the given points as its vertices and the distances between points as edge weights. The same points may have more than one minimum spanning tree. For instance, for the vertices of a regular polygon, removing any edge of the polygon produces a minimum spanning tree.

Publications on the Euclidean minimum spanning tree commonly abbreviate it as "EMST". They may also be called "geometric minimum spanning trees", but that term may be used more generally for geometric spaces with non-Euclidean distances, such as $L^{p}$ spaces. When the context of Euclidean point sets is clear, they may be called simply "minimum spanning trees".

Several other standard geometric networks are closely related to the Euclidean minimum spanning tree:
 * The Steiner tree problem again seeks a system of line segments connecting all given points, but without requiring the segments to start and end only at given points. In this problem, additional points may be added as segment endpoints, allowing the Steiner tree to be shorter than the minimum spanning tree.
 * In the Euclidean traveling salesperson path problem, the connecting line segments must start and end at the given points, like the spanning tree and unlike the Steiner tree; additionally, each point can touch at most two line segments, so the result forms a polygonal chain. Because of this restriction, the optimal path may be longer than the Euclidean minimum spanning tree, but is at most twice as long.
 * Geometric spanners are low-weight networks that, like the minimum spanning tree, connect all of the points. Unlike the minimum spanning tree, all of these connecting paths are required to be short, having length proportional to the distance between the points they connect. To achieve this property, these networks generally have cycles and so are not trees.

Angles and vertex degrees
Whenever two edges of a Euclidean minimum spanning tree meet at a vertex, they must form an angle of 60° or more, with equality only when they form two sides of an equilateral triangle. This is because, for two edges forming any sharper angle, one of the two edges could be replaced by the third, shorter edge of the triangle they form, forming a tree with smaller total length. In comparison, the Steiner tree problem has a stronger angle bound: an optimal Steiner tree has all angles at least 120°.

The same 60° angle bound also occurs in the kissing number problem, of finding the maximum number of unit spheres in Euclidean space that can be tangent to a central unit sphere without any two spheres intersecting (beyond a point of tangency). The center points of these spheres have a minimum spanning tree in the form of a star, with the central point adjacent to all other points. Conversely, for any vertex $$v$$ of any minimum spanning tree, one can construct non-overlapping unit spheres centered at $$v$$ and at points two units along each of its edges, with a tangency for each neighbor of $$v$$. Therefore, in $$n$$-dimensional space the maximum possible degree of a vertex (the number of spanning tree edges connected to it) equals the kissing number of spheres in $$n$$ dimensions. Planar minimum spanning trees have degree at most six, and when a tree has degree six there is always another minimum spanning tree with maximum degree five. Three-dimensional minimum spanning trees have degree at most twelve. The only higher dimensions in which the exact value of the kissing number is known are four, eight, and 24 dimensions.

For points generated at random from a given continuous distribution, the minimum spanning tree is almost surely unique. The numbers of vertices of any given degree converge, for large number of vertices, to a constant times that number of vertices. The values of these constants depend on the degree and the distribution. However, even for simple cases—such as the number of leaves for points uniformly distributed in a unit square—their precise values are not known.

Empty regions
For any edge $$uv$$ of any Euclidean minimum spanning tree, the lens (or vesica piscis) formed by intersecting the two circles with $$uv$$ as their radii cannot have any other given vertex $$w$$ in its interior. Put another way, if any tree has an edge $$uv$$ whose lens contains a third point $$w$$, then it is not of minimum length. For, by the geometry of the two circles, $$w$$ would be closer to both $$u$$ and $$v$$ than they are to each other. If edge $$uv$$ were removed from the tree, $$w$$ would remain connected to one of $$u$$ and $$v$$, but not the other. Replacing the removed edge $$uv$$ by $$uw$$ or $$vw$$ (whichever of these two edges reconnects $$w$$ to the vertex from which it was disconnected) would produce a shorter tree.

For any edge $$uv$$ of any Euclidean minimum spanning tree, the rhombus with angles of 60° and 120°, having $$uv$$ as its long diagonal, is disjoint from the rhombi formed analogously by all other edges. Two edges sharing an endpoint cannot have overlapping rhombi, because that would imply an edge angle sharper than 60°, and two disjoint edges cannot have overlapping rhombi; if they did, the longer of the two edges could be replaced by a shorter edge among the same four vertices.

Supergraphs
Certain geometric graphs have definitions involving empty regions in point sets, from which it follows that they contain every edge that can be part of a Euclidean minimum spanning tree. These include: Because the empty-region criteria for these graphs are progressively weaker, these graphs form an ordered sequence of subgraphs. That is, using "⊆" to denote the subset relationship among their edges, these graphs have the relations:
 * The relative neighborhood graph, which has an edge between any pair of points whenever the lens they define is empty.
 * The Gabriel graph, which has an edge between any pair of points whenever the circle having the pair as a diameter is empty.
 * The Delaunay triangulation, which has an edge between any pair of points whenever there exists an empty circle having the pair as a chord.
 * The Urquhart graph, formed from the Delaunay triangulation by removing the longest edge of each triangle. For each remaining edge, the vertices of the Delaunay triangles that use that edge cannot lie within the empty lune of the relative neighborhood graph.

Another graph guaranteed to contain the minimum spanning tree is the Yao graph, determined for points in the plane by dividing the plane around each point into six 60° wedges and connecting each point to the nearest neighbor in each wedge. The resulting graph contains the relative neighborhood graph, because two vertices with an empty lens must be the nearest neighbors to each other in their wedges. As with many of the other geometric graphs above, this definition can be generalized to higher dimensions, and (unlike the Delaunay triangulation) its generalizations always include a linear number of edges.

Total length
For $$n$$ points in the unit square (or any other fixed shape), the total length of the minimum spanning tree edges is $$O(\sqrt n)$$. Some sets of points, such as points evenly spaced in a $$\sqrt n \times \sqrt n$$ grid, attain this bound. For points in a unit hypercube in $$d$$-dimensional space, the corresponding bound is $$O(n^{(d-1)/d})$$. The same bound applies to the expected total length of the minimum spanning tree for $$n$$ points chosen uniformly and independently from a unit square or unit hypercube. Returning to the unit square, the sum of squared edge lengths of the minimum spanning tree is $$O(1)$$. This bound follows from the observation that the edges have disjoint rhombi, with area proportional to the edge lengths squared. The $$O(\sqrt n)$$ bound on total length follows by application of the Cauchy–Schwarz inequality.

Another interpretation of these results is that the average edge length for any set of points in a unit square is $$O(1/\sqrt n)$$, at most proportional to the spacing of points in a regular grid; and that for random points in a unit square the average length is proportional to $$1/\sqrt n$$. However, in the random case, with high probability the longest edge has length approximately $$\sqrt{\frac{\log n}{\pi n}},$$ longer than the average by a non-constant factor. With high probability, the longest edge forms a leaf of the spanning tree, and connects a point far from all the other points to its nearest neighbor. For large numbers of points, the distribution of the longest edge length around its expected value converges to a Gumbel distribution.

Any geometric spanner, a subgraph of a complete geometric graph whose shortest paths approximate the Euclidean distance, must have total edge length at least as large as the minimum spanning tree, and one of the standard quality measures for a geometric spanner is the ratio between its total length and of the minimum spanning tree for the same points. Several methods for constructing spanners, such as the greedy geometric spanner, achieve a constant bound for this ratio. It has been conjectured that the Steiner ratio, the largest possible ratio between the total length of a minimum spanning tree and Steiner tree for the same set of points in the plane, is $$2/\sqrt{3}\approx 1.1547$$, the ratio for three points in an equilateral triangle.

Subdivision
If every edge of a Euclidean minimum spanning tree is subdivided, by adding a new point at its midpoint, then the resulting tree is still a minimum spanning tree of the augmented point set. Repeating this subdivision process allows a Euclidean minimum spanning tree to be subdivided arbitrarily finely. However, subdividing only some of the edges, or subdividing the edges at points other than the midpoint, may produce a point set for which the subdivided tree is not the minimum spanning tree.

Computational complexity
For points in any dimension, the minimum spanning tree can be constructed in time $$O(n^2)$$ by constructing a complete graph with an edge between every pair of points, weighted by Euclidean distance, and then applying a graph minimum spanning tree algorithm such as the Prim–Dijkstra–Jarník algorithm or Borůvka's algorithm on it. These algorithms can be made to take time $$O(n^2)$$ on complete graphs, unlike another common choice, Kruskal's algorithm, which is slower because it involves sorting all distances. For points in low-dimensional spaces, the problem may be solved more quickly, as detailed below.

Computing Euclidean distances involves a square root calculation. In any comparison of edge weights, comparing the squares of the Euclidean distances, instead of the distances themselves, yields the same ordering, and so does not change the rest of the tree's computation. This shortcut speeds up calculation and allows a minimum spanning tree for points with integer coordinates to be constructed using only integer arithmetic.

Two dimensions
A faster approach to finding the minimum spanning tree of planar points uses the property that it is a subgraph of the Delaunay triangulation: The result is an algorithm taking $$O(n\log n)$$ time, optimal in certain models of computation (see below).
 * 1) Compute the Delaunay triangulation, which can be done in $$O(n\log n)$$ time. Because the Delaunay triangulation is a planar graph, it has at most $$3n-6$$ edges.
 * 2) Label each edge with its (squared) length.
 * 3) Run a graph minimum spanning tree algorithm. Since there are $$O(n)$$ edges, this requires $$O(n\log n)$$ time using any of the standard minimum spanning tree algorithms.

If the input coordinates are integers and can be used as array indices, faster algorithms are possible: the Delaunay triangulation can be constructed by a randomized algorithm in $$O(n\log\log n)$$ expected time. Additionally, since the Delaunay triangulation is a planar graph, its minimum spanning tree can be found in linear time by a variant of Borůvka's algorithm that removes all but the cheapest edge between each pair of components after each stage of the algorithm. Therefore, the total expected time for this algorithm is $$O(n\log\log n)$$. In the other direction, the Delaunay triangulation can be constructed from the minimum spanning tree in the near-linear time bound $$O(n\log^* n)$$, where $$\log^*$$ denotes the iterated logarithm.

Higher dimensions
The problem can also be generalized to $$n$$ points in the $$d$$-dimensional space $$\R^d$$. In higher dimensions, the connectivity determined by the Delaunay triangulation (which, likewise, partitions the convex hull into $$d$$-dimensional simplices) contains the minimum spanning tree; however, the triangulation might contain the complete graph. Therefore, finding the Euclidean minimum spanning tree as a spanning tree of the complete graph or as a spanning tree of the Delaunay triangulation both take $$O(dn^2)$$ time. For three dimensions the minimum spanning tree can be found in time $$O\bigl((n\log n)^{4/3}\bigr)$$, and in any greater dimension, in time $$O\left(n^{2-\frac{2}{\lceil d/2\rceil+1}+\varepsilon}\right)$$ for any $$\varepsilon>0$$—faster than the quadratic time bound for the complete graph and Delaunay triangulation algorithms.

The optimal time complexity for higher-dimensional minimum spanning trees remains unknown, but is closely related to the complexity of computing bichromatic closest pairs. In the bichromatic closest pair problem, the input is a set of points, given two different colors (say, red and blue). The output is a pair of a red point and a blue point with the minimum possible distance. This pair always forms one of the edges in the minimum spanning tree. Therefore, the bichromatic closest pair problem can be solved in the amount of time that it takes to construct a minimum spanning tree and scan its edges for the shortest red–blue edge. Conversely, for any red–blue coloring of any subset of a given set of points, the bichromatic closest pair produces one edge of the minimum spanning tree of the subset. By carefully choosing a sequence of colorings of subsets, and finding the bichromatic closest pair of each subproblem, the minimum spanning tree may be found in time proportional to the optimal time for finding bichromatic closest pairs for the same number of points, whatever that optimal time turns out to be.

For uniformly random point sets in any bounded dimension, the Yao graph or Delaunay triangulation have linear expected numbers of edges, are guaranteed to contain the minimum spanning tree, and can be constructed in linear expected time. From these graphs, the minimum spanning tree itself may be constructed in linear time, by using a randomized linear time algorithm for graph minimum spanning trees. However, the poor performance of these methods on inputs coming from clustered data has led algorithm engineering researchers to develop methods with a somewhat slower $$O(n\log n)$$ time bound, for random inputs or inputs whose distances and clustering resemble those of random data, while exhibiting better performance on real-world data.

A well-separated pair decomposition is a family of pairs of subsets of the given points, so that every pair of points belong to one of these pairs of subsets, and so that all pairs of points coming from the same pair of subsets have approximately the same length. It is possible to find a well-separated pair decomposition with a linear number of subsets, and a representative pair of points for each subset, in time $$O(n\log n)$$. The minimum spanning tree of the graph formed by these representative pairs is then an approximation to the minimum spanning tree. Using these ideas, a $$(1+\varepsilon)$$-approximation to the minimum spanning tree may be found in $$O(n\log n)$$ time, for constant $$\varepsilon$$. More precisely, by choosing each representative pair to approximate the closest pair in its equivalence class, and carefully varying the quality of this approximation for different pairs, the dependence on $$\varepsilon$$ in the time bound can be given as $$O(n \log n + (\varepsilon^{-2} \log ^2 \tfrac{1}{\varepsilon})n),$$ for any fixed dimension.

Dynamic and kinetic
The Euclidean minimum spanning tree has been generalized in many different ways to systems of moving or changing points:
 * If a set of points undergoes a sequence of dynamic insertions or deletions of points, each of these updates induces a bounded amount of change to the minimum spanning tree of the points. When the update sequence is known in advance, for points in the plane, the change after each insertion or deletion can be found in time $$O(\log^2 n)$$ per insertion or deletion. When the updates must be handled in an online manner, a slower (but still poly-logarithmic) $$O(\log^{10} n)$$ time bound is known. For higher-dimensional versions of the problem the time per update is slower, but still sublinear.
 * For $$n$$ points moving linearly with constant speed, or with more general algebraic motions, the minimum spanning tree will change by a sequence of swaps, in which one edge is removed and another replaces it at a point in time where both have equal length. For linear motions, the number of changes is at most slightly larger than $$n^{25/9}$$. For more general algebraic motions, there is a near-cubic upper bound on the number of swaps, based on the theory of Davenport–Schinzel sequences.
 * The minimum moving spanning tree problem again concerns points moving linearly with constant speed, over an interval of time, and seeks a single tree that minimizes the maximum sum of weights occurring at any instant during this interval. It is NP-hard to compute exactly, but can be approximated to within a factor of two in polynomial time.
 * The kinetic Euclidean minimum spanning tree problem asks for a kinetic data structure that can maintain the minimum spanning tree as its points undergo both continuous motions and insertions and deletions. Several papers have studied such structures, and a kinetic structure for algebraically moving points with near-cubic total time, nearly matching the bound on the number of swaps, is known.

Lower bound
An asymptotic lower bound of $$\Omega(n\log n)$$ of the Euclidean minimum spanning tree problem can be established in restricted models of computation. These include the algebraic decision tree and algebraic computation tree models, in which the algorithm has access to the input points only through certain restricted primitives that perform simple algebraic computations on their coordinates. In these models, the closest pair of points problem requires $$\Omega(n\log n)$$ time, but the closest pair is necessarily an edge of the minimum spanning tree, so the minimum spanning tree also requires this much time. Therefore, algorithms for constructing the planar minimum spanning tree in time $$O(n\log n)$$ within this model, for instance by using the Delaunay triangulation, are optimal. However, these lower bounds do not apply to models of computation with integer point coordinates, in which bitwise operations and table indexing operations on those coordinates are permitted. In these models, faster algorithms are possible, as described above.

Applications
An obvious application of Euclidean minimum spanning trees is to find the cheapest network of wires or pipes to connect a set of places, assuming the links cost a fixed amount per unit length. The first publications on minimum spanning trees more generally concerned a geographic version of the problem, involving the design of an electrical grid for southern Moravia, and an application to minimizing wire lengths in circuits was described in 1957 by Loberman and Weinberger.

Minimum spanning trees are closely related to single-linkage clustering, one of several methods for hierarchical clustering. The edges of a minimum spanning tree, sorted by their length, give the order in which to merge clusters into larger clusters in this clustering method. Once these edges have been found, by any algorithm, they may be used to construct the single-linkage clustering in time $$O(n\log n)$$. Although the long thin cluster shapes produced by single-linkage clustering can be a bad fit for certain types of data, such as mixtures of Gaussian distributions, it can be a good choice in applications where the clusters themselves are expected to have long thin shapes, such as in modeling the dark matter halos of galaxies. In geographic information science, several researcher groups have used minimum spanning trees of the centroids of buildings to identify meaningful clusters of buildings, for instance by removing edges identified in some other way as inconsistent.

Minimum spanning trees have also been used to infer the shape of curves in the plane, given points sampled along the curve. For a smooth curve, sampled more finely than its local feature size, the minimum spanning tree will form a path connecting consecutive points along the curve. More generally, similar methods can recognize curves drawn in a dotted or dashed style rather than as a single connected set. Applications of this curve-finding technique include particle physics, in automatically identifying the tracks left by particles in a bubble chamber. More sophisticated versions of this idea can find curves from a cloud of noisy sample points that roughly follows the curve outline, by using the topology of the spanning tree to guide a moving least squares method.

Another application of minimum spanning trees is a constant-factor approximation algorithm for the Euclidean traveling salesman problem, the problem of finding the shortest polygonalization of a point set. Walking around the boundary of the minimum spanning tree can approximate the optimal traveling salesman tour within a factor of two of the optimal length. However, more accurate polynomial-time approximation schemes are known for this problem. In wireless ad hoc networks, broadcasting messages along paths in a minimum spanning tree can be an accurate approximation to the minimum-energy broadcast routing, which is, again, hard to compute exactly.

Realization
The realization problem for Euclidean minimum spanning trees takes an abstract tree as input and seeks a geometric location for each vertex of the tree (in a space of some fixed dimension), such that the given tree equals the minimum spanning tree of those points. Not every abstract tree has such a realization; for instance, the tree must obey the kissing number bound on the degree of each vertex. Additional restrictions exist; for instance, it is not possible for a planar minimum spanning tree to have a degree-six vertex adjacent to a vertex of degree five or six. Determining whether a two-dimensional realization exists is NP-hard. However, the proof of hardness depends on the fact that degree-six vertices in a tree have a very restricted set of realizations: the neighbors of such a vertex must be placed on the vertices of a regular hexagon centered at that vertex. Indeed, for trees of maximum degree five, a planar realization always exists. Similarly, for trees of maximum degree ten, a three-dimensional realization always exists. For these realizations, some trees may require edges of exponential length and bounding boxes of exponential area relative to the length of their shortest edge. Trees of maximum degree four have smaller planar realizations, with polynomially bounded edge lengths and bounding boxes.

title: Euclidean minimum spanning tree


text:
Talk:Gordon Cooper/to do

Incorporate NASA profile in article.

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

title: Talk:Gordon Cooper/to do


text:
Pre-dreadnought battleship

Pre-dreadnought battleships were sea-going battleships built from the mid- to late- 1880s to the early 1900s. Their designs were conceived before the appearance of HMS Dreadnought (1906) in 1906 and their classification as "pre-dreadnought" is retrospectively applied. In their day, they were simply known as "battleships" or else more rank-specific terms such as "first-class battleship" and so forth. The pre-dreadnought battleships were the pre-eminent warships of their time and replaced the ironclad battleships of the 1870s and 1880s.

In contrast to the multifarious development of ironclads in preceding decades, the 1890s saw navies worldwide start to build battleships to a common design as dozens of ships essentially followed the design of the Royal Navy's Majestic-class battleship. Built from steel, protected by compound, nickel steel or case-hardened steel armour, pre-dreadnought battleships were driven by coal-fired boilers powering compound reciprocating steam engines which turned underwater screws. These ships distinctively carried a main battery of very heavy guns upon the weather deck, in large rotating mounts either fully or partially armoured over, and supported by one or more secondary batteries of lighter weapons on broadside.

The similarity in appearance of battleships in the 1890s was underlined by the increasing number of ships being built. New naval powers such as Germany, Japan, the United States, and to a lesser extent Italy and Austria-Hungary, began to establish themselves with fleets of pre-dreadnoughts. Meanwhile, the battleship fleets of the United Kingdom, France, and Russia expanded to meet these new threats. The last decisive clash of pre-dreadnought fleets was between the Imperial Japanese Navy and the Imperial Russian Navy at the Battle of Tsushima on 27 May 1905.

These battleships were abruptly made obsolete by the arrival of HMS Dreadnought in 1906. Dreadnought followed the trend in battleship design to heavier, longer-ranged guns by adopting an "all-big-gun" armament scheme of ten 12-inch guns. Her innovative steam turbine engines also made her faster. The existing battleships were decisively outclassed, with no more being designed to their format thereafter; the new, larger and more powerful, battleships built from then on were known as dreadnoughts. This was the point at which the ships that had been laid down before were redesignated "pre-dreadnoughts".

Evolution

The pre-dreadnought developed from the ironclad battleship. The first ironclads—the French Gloire and HMS Warrior (1860)—looked much like sailing frigates, with three tall masts and broadside batteries, when they were commissioned in the early 1860s. HMVS Cerberus, the first breastwork monitor, was launched in 1868, followed in 1871 by HMS Devastation (1871), a turreted ironclad which more resembled a pre-dreadnought than the previous, and its contemporary, turretless ironclads. Both ships dispensed with masts and carried four heavy guns in two turrets fore and aft. Devastation was the first ocean-worthy breastwork monitor; because of her very low freeboard, her decks were subject to being swept by water and spray, interfering with the working of her guns. Navies worldwide continued to build masted, turretless battleships which had sufficient freeboard and were seaworthy enough to fight on the high seas.

The distinction between coast-assault battleship and cruising battleship became blurred with the Admiral-class ironclads, ordered in 1880. These ships reflected developments in ironclad design, being protected by iron-and-steel compound armour rather than wrought iron. Equipped with breech-loading guns of between 12-inch and 16 ¼-inch (305 mm and 413 mm) calibre, the Admirals continued the trend of ironclad warships mounting gigantic weapons. The guns were mounted in open barbettes to save weight. Some historians see these ships as a vital step towards pre-dreadnoughts; others view them as a confused and unsuccessful design.

The subsequent Royal Sovereign-class battleship of 1889 retained barbettes but were uniformly armed with 13.5 in guns; they were also significantly larger (at 14,000 tons displacement) and faster (because of triple-expansion steam engines) than the Admirals. Just as importantly, the Royal Sovereigns had a higher freeboard, making them unequivocally capable of the high-seas battleship role.

The pre-dreadnought design reached maturity in 1895 with the Majestic-class battleship. These ships were built and armoured entirely of steel, and their guns were now mounted in fully-enclosed rotating turrets. They also adopted 12 in main guns, which, because of advances in gun construction and the use of cordite propellant, were lighter and more powerful than the previous guns of larger calibre. The Majestics provided the model for battleship building in the Royal Navy and many other navies for years to come.

Armament
Pre-dreadnoughts carried guns of several different calibres, for different roles in ship-to-ship combat.

Main battery

Very few pre-dreadnoughts deviated from what became the classic arrangement of heavy weaponry: A main battery of four heavy guns mounted in two centre-line gunhouses fore and aft (these could be either fully enclosed barbettes or true turrets but, regardless of type, were later to be universally referred to as 'turrets'). These main guns were slow-firing, and initially of limited accuracy; but they were the only guns heavy enough to penetrate the thick armour which protected the engines, magazines, and main guns of enemy battleships.

The most common calibre for this main armament was 12 in, although earlier ships often had larger-calibre weapons of lower muzzle velocity (guns in the 13-inch to 14-inch range) and some designs used smaller guns because they could attain higher rates of fire. All British first-class battleships from the Majestic class onwards carried 12-inch weapons, as did French battleships from the Charlemagne-class battleship class, laid down in 1894. Japan, importing most of its guns from Britain, used this calibre also. The United States used both 12 in and 13 in guns for most of the 1890s until the Maine-class battleship, laid down in 1899 (not the earlier USS Maine (ACR-1) of Spanish–American War notoriety), after which the 12-inch gun was universal. The Russians used both 12 and 10 in as their main armament; the Petropavlovsk-class battleship, RUSSIAN BATTLESHIP Retvizan, RUSSIAN BATTLESHIP Tsesarevich, and Borodino-class battleship had 12 in main batteries while the Peresvet-class battleship mounted 10 in guns. The first German pre-dreadnought class used an 11 in gun but decreased to a 9.4 in gun for the two following classes and returned to 11-inch guns with the Braunschweig-class battleship.

While the calibre of the main battery remained quite constant, the performance of the guns improved as longer barrels were introduced. The introduction of slow-burning nitrocellulose and cordite propellant allowed the employment of a longer barrel, and therefore higher muzzle velocity—giving greater range and penetrating power for the same calibre of shell. Between the Majestic class and Dreadnought, the length of the British 12-inch gun increased from 35 calibres to 45. and muzzle velocity increased from 2317 feet per second to 2525 feet per second.

Secondary battery
Pre-dreadnoughts also carried a secondary battery of smaller guns, typically 6 in, though calibres from 4 to 9.4 inches (100 to 240 mm) were used. Virtually all secondary guns were "quick firing", employing a number of innovations to increase the rate of fire. The propellant was provided in a brass cartridge, and both the breech mechanism and the mounting were suitable for rapid aiming and reloading. A principal role of the secondary battery was to damage the less armoured parts of an enemy battleship; while unable to penetrate the main armour belt, it might score hits on lightly armoured areas like the bridge, or start fires. Equally important, the secondary armament was to be used against smaller enemy vessels such as cruisers, destroyers, and even torpedo boats. A medium-calibre gun could expect to penetrate the light armour of smaller ships, while the rate of fire of the secondary battery was important in scoring a hit against a small, manoeuvrable target. Secondary guns were mounted in a variety of ways; sometimes carried in turrets, they were just as often positioned in fixed armoured casemates in the side of the hull, or in unarmoured positions on upper decks.

Intermediate battery
Some of the pre-dreadnoughts carried an "intermediate" battery, typically of 8 to 10 inch calibre. The intermediate battery was a method of packing more heavy firepower into the same battleship, principally of use against battleships or at long ranges. The United States Navy pioneered the intermediate battery concept in the Indiana-class battleship, USS Iowa (BB-4), and Kearsarge-class battleship classes, but not in the battleships laid down between 1897 and 1901. Shortly after the USN re-adopted the intermediate battery, the British, Italian, Russian, French, and Japanese navies laid down intermediate-battery ships. Almost all of this later generation of intermediate-battery ships finished building after Dreadnought, and hence were obsolescent before completion.

Tertiary battery
The pre-dreadnought's armament was completed by a tertiary battery of light, rapid-fire guns, of any calibre from 3-inch (76 mm) down to machine guns. Their role was to give short-range protection against torpedo boats, or to rake the deck and superstructure of a battleship.

Torpedoes
In addition to their gun armament, many pre-dreadnought battleships were armed with torpedoes, fired from fixed tubes located either just above or below the waterline. By the pre-dreadnought era the torpedo was typically 18 in in diameter and had an effective range of several thousand metres. However, it was virtually unknown for a battleship to score a hit with a torpedo.

Range of combat
During the ironclad age, the range of engagements increased; in the Sino-Japanese War of 1894–95 battles were fought at around 1 mile (1.5 km), while in the Battle of the Yellow Sea in 1904, the Russian and Japanese fleets fought at ranges of 3.5 miles (5.5 km). The increase in engagement range was due in part to the longer range of torpedoes, and in part to improved gunnery and fire control. In consequence, shipbuilders tended towards heavier secondary armament, of the same calibre that the "intermediate" battery had been; the Royal Navy's last pre-dreadnought class, the Lord Nelson class, carried ten 9.2-inch guns as secondary armament. Ships with a uniform, heavy secondary battery are often referred to as "semi-dreadnoughts".

Protection

Pre-dreadnought battleships carried a considerable weight of steel armour, providing them with effective defence against the great majority of naval guns in service during the period. 'Medium' calibre guns up to 8-9.4 inch would generally prove incapable of piercing their thickest armour, while it still provided some measure of defence against even the 'heavy' guns of the day which were considered capable of piercing these plates.

Vertical side armour
Experience with the first generations of ironclads showed that rather than giving the ship's entire length uniform armour protection, it was best to concentrate armour in greater thickness over limited but critical areas. Therefore the central section of the hull, which housed the boilers and engines, was protected by the main belt, which ran from just below the waterline to some distance above it. This "central citadel" was intended to protect the engines from even the most powerful shells. Yet the emergence of the quick-firing gun and high explosives in the 1880s meant that the 1870s to early 1880s concept of the pure central citadel was also inadequate in the 1890s and that thinner armour extensions towards the extremities would greatly aid the ship's defensive qualities. Thus, the main belt armour would normally taper to a lesser thickness along the side of the hull towards bow and stern; it might also taper up from the central citadel towards the superstructure.

Other armour
The main armament and the magazines were protected by projections of thick armour from the main belt. The beginning of the pre-dreadnought era was marked by a move from mounting the main armament in open barbettes to an all-enclosed, turret mounting.

The deck was typically lightly armoured with 2 to 4 inches of steel. This lighter armour was to prevent high-explosive shells from wrecking the superstructure of the ship.

The majority of battleships during this period of construction were fitted with a heavily-armoured conning tower, or CT, which was intended for the use of the command staff during battle. This was protected by a vertical, full height, ring of armour nearly equivalent in thickness to the main battery gunhouses and provided with observation slits. A narrow armoured tube extended down below this to the citadel; this contained & protected the various voice-tubes used for communication from the CT to various key stations during battle.

Metallurgical advances in armour
The battleships of the late 1880s, for instance the Royal Sovereign class, were armoured with iron and steel compound armour. This was soon replaced with more effective case-hardened steel armour made using the Harvey process developed in the United States. First tested in 1891, Harvey armour was commonplace in ships laid down from 1893 to 1895. However, its reign was brief; in 1895, the German SMS Kaiser Friedrich III pioneered the superior Krupp armour. Europe adopted Krupp plate within five years, and only the United States persisted in using Harvey steel into the 20th century. The improving quality of armour plate meant that new ships could have better protection from a thinner and lighter armour belt; 12 inches (305 mm) of compound armour provided the same protection as just 7.5 inches (190 mm) of Harvey or 5.75 inches (133 mm) of Krupp.

Propulsion

Almost all pre-dreadnoughts were powered by reciprocating steam engines. Most were capable of top speeds between 16 and 18 kn. The ironclads of the 1880s used compound engines, and by the end of the 1880s the even-more efficient triple expansion compound engine was in use. Some fleets, though not the British, adopted the quadruple-expansion steam engine.

The main improvement in engine performance during the pre-dreadnought period came from the adoption of increasingly higher pressure steam from the boiler. Scotch marine boilers were superseded by more compact water-tube boilers, allowing higher-pressure steam to be produced with less fuel consumption. Water-tube boilers were also safer, with less risk of explosion, and more flexible than fire-tube types. The Belleville-type water-tube boiler had been introduced in the French fleet as early as 1879, but it took until 1894 for the Royal Navy to adopt it for armoured cruisers and pre-dreadnoughts; other water-tube boilers followed in navies worldwide.

The engines drove either two or three screw propellers. France and Germany preferred the three-screw approach, which allowed the engines to be shorter and hence more easily protected; they were also more maneuverable and had better resistance to accidental damage. Triple screws were, however, generally larger and heavier than the twin-screw arrangements preferred by most other navies.

Coal was the almost exclusive fuel for the pre-dreadnought period, though navies made the first experiments with oil propulsion in the late 1890s. An extra knot or two of speed could be gained for short bursts by applying a 'forced draught' to the furnaces, where air was pumped into the furnaces, but this risked damage to the boilers if used for prolonged periods.

The French built the only class of turbine powered pre-dreadnought battleships, the Danton-class battleship of 1907.

Pre-dreadnought fleets and battles

The pre-dreadnought battleship in its heyday was the core of a very diverse navy. Many older ironclads were still in service. Battleships served alongside cruisers of many descriptions: modern armoured cruisers which were essentially cut-down battleships, lighter protected cruisers, and even older unarmoured cruisers, sloops and frigates whether built out of steel, iron or wood. The battleships were threatened by torpedo boats; it was during the pre-dreadnought era that the first destroyers were constructed to deal with the torpedo-boat threat, though at the same time the first effective submarines were being constructed.

The pre-dreadnought age saw the beginning of the end of the 19th century naval balance of power in which France and Russia vied for competition against the massive Royal Navy, and saw the start of the rise of the "new naval powers" of Germany, Japan and the United States. The new ships of the Imperial Japanese Navy and to a lesser extent the U.S. Navy supported those powers' colonial expansion.

While pre-dreadnoughts were adopted worldwide, there were no clashes between pre-dreadnought battleships until the very end of their period of dominance. The First Sino-Japanese War in 1894–95 influenced pre-dreadnought development, but this had been a clash between Chinese battleships and a Japanese fleet consisting of mostly cruisers. The Spanish–American War of 1898 was also a mismatch, with the American pre-dreadnought fleet engaging Spanish shore batteries at San Juan and then a Spanish squadron of armoured cruisers and destroyers at the Battle of Santiago de Cuba. Not until the Russo-Japanese War of 1904–05 did pre-dreadnoughts engage on an equal footing. This happened in three battles: the Russian tactical victory during the Battle of Port Arthur on 8–9 February 1904, the indecisive Battle of the Yellow Sea on 10 August 1904, and the decisive Japanese victory at the Battle of Tsushima on 27 May 1905. These battles upended prevailing theories of how naval battles would be fought, as the fleets began firing at one another at much greater distances than before; naval architects realized that plunging fire (explosive shells falling on their targets largely from above, instead of from a trajectory close to horizontal) was a much greater threat than had been thought.

Gunboat diplomacy was typically conducted by cruisers or smaller warships. A British squadron of three protected cruisers and two gunboats brought about the capitulation of Zanzibar in 1896; and while battleships participated in the combined fleet Western powers deployed during the Boxer Rebellion, the naval part of the action was performed by gunboats, destroyers and sloops.

Europe

European navies remained dominant in the pre-dreadnought era. The Royal Navy remained the world's largest fleet, though both Britain's traditional naval rivals and the new European powers increasingly asserted themselves against its supremacy.

In 1889, Britain formally adopted a "two power standard" committing it to building enough battleships to exceed the two largest other navies combined; at the time, this meant France and Russia, which became formally allied in the early 1890s. The Royal Sovereign and Majestic classes were followed by a regular programme of construction at a much quicker pace than in previous years. The Canopus-class battleship, Formidable-class battleship, Duncan-class battleship and King Edward VII-class battleship classes appeared in rapid succession from 1897 to 1905. Counting two ships ordered by Chile but taken over by the British, the Royal Navy had 50 pre-dreadnought battleships ready or being built by 1904, from the 1889 Naval Defence Act's ten units onwards. Over a dozen older battleships remained in service. The last two British pre-dreadnoughts, the "semi-dreadnought" Lord Nelsons, appeared after Dreadnought herself.

France, Britain's traditional naval rival, had paused its battleship building during the 1880s because of the influence of the Jeune École doctrine, which favoured torpedo boats to battleships. After the Jeune École's influence faded, the first French battleship laid down was FRENCH BATTLESHIP Brennus, in 1889. Brennus and the ships which followed her were individual, as opposed to the large classes of British ships; they also carried an idiosyncratic arrangement of heavy guns, with Brennus carrying three 13.4 in guns and the ships which followed carrying two 12-inch and two 10.8-inch guns in single turrets. The Charlemagne class, laid down 1894–1896, were the first to adopt the standard four 12 in gun heavy armament. The Jeune École retained a strong influence on French naval strategy, and by the end of the 19th century France had abandoned competition with Britain in battleship numbers. The French suffered the most from the dreadnought revolution, with four ships of the Liberté-class battleship still building when Dreadnought launched, and a further six of the Danton class begun afterwards.

Germany's first pre-dreadnoughts, the Brandenburg-class battleship, were laid down in 1890. By 1905, a further 19 battleships were built or under construction, thanks to the sharp increase in naval expenditure justified by the 1898 and 1900 Navy Laws. This increase was due to the determination of the navy chief Alfred von Tirpitz and the growing sense of national rivalry with the UK. Besides the Brandenburg class, German pre-dreadnoughts include the ships of the Kaiser Friedrich III-class battleship, Wittelsbach-class battleship, and Braunschweig classes—culminating in the Deutschland-class battleship, which served in both world wars. On the whole, the German ships were less powerful than their British equivalents but equally robust.

Russia equally entered into a programme of naval expansion in the 1890s; one of Russia's main objectives was to maintain its interests against Japanese expansion in the Far East. The Petropavlovsk class begun in 1892 took after the British Royal Sovereigns; later ships showed more French influence on their designs, such as the Borodino class. The weakness of Russian shipbuilding meant that many ships were built overseas for Russia; the best ship, the Retvizan, being largely constructed in the United States. The Russo-Japanese War of 1904–05 was a disaster for the Russian pre-dreadnoughts; of the 15 battleships completed since Petropavlovsk, eleven were sunk or captured during the war. One of these, the famous RUSSIAN BATTLESHIP Potemkin, mutinied and was briefly taken over by Romania at the end of the mutiny. However, she was soon recovered and recommissioned as Panteleimon. After the war, Russia completed four more pre-dreadnoughts after 1905.

Between 1893 and 1904, Italy laid down eight battleships; the later two classes of ship were remarkably fast, though the Regina Margherita-class battleship was poorly protected and the Regina Elena-class battleship lightly armed. In some ways, these ships presaged the concept of the battlecruiser. The Austro-Hungarian Empire also saw a naval renaissance during the 1890s, though of the nine pre-dreadnought battleships ordered only the three of the Habsburg class arrived before Dreadnought herself made them obsolete.

America and the Pacific

The United States started building its first battleships in 1891. These ships were short-range coast-defence battleships that were similar to the British HMS Hood (1891) except for an innovative intermediate battery of 8-inch guns. The US Navy continued to build ships that were relatively short-range and poor in heavy seas, until the Virginia-class battleship laid down in 1901–02. Nevertheless, it was these earlier ships that ensured American naval dominance against the antiquated Spanish fleet—which included no pre-dreadnoughts—in the Spanish–American War, most notably at the Battle of Santiago de Cuba. The final two classes of American pre-dreadnoughts (the Connecticut-class battleships and Mississippi-class battleships) were completed after the completion of the Dreadnought and after the start of design work on the USN's own initial class of dreadnoughts. The US Great White Fleet of 16 pre-dreadnought battleships circumnavigated the world from 16 December 1907, to 22 February 1909.

Japan was involved in two of the three major naval wars of the pre-dreadnought era. The first Japanese pre-dreadnought battleships, the Fuji class, were still being built at the outbreak of the First Sino-Japanese War of 1894–95, which saw Japanese armoured cruisers and protected cruisers defeat the Chinese Beiyang Fleet, composed of a mixture of old ironclad battleships and cruisers, at the Battle of the Yalu River. Following their victory, and facing Russian pressure in the region, the Japanese placed orders for four more pre-dreadnoughts; along with the two Fujis these battleships formed the core of the fleet which twice engaged the numerically superior Russian fleets at the Battle of the Yellow Sea and the Battle of Tsushima. After capturing eight Russian battleships of various ages, Japan built several more classes of pre-dreadnoughts after the Russo-Japanese War.

Obsolescence

In 1906, the commissioning of HMS Dreadnought (1906) brought about the obsolescence of all existing battleships. Dreadnought, by scrapping the secondary battery, was able to carry ten 12 in guns rather than four. She could fire eight heavy guns broadside, as opposed to four from a pre-dreadnought; and six guns ahead, as opposed to two. The move to an "all-big-gun" design was a logical conclusion of the increasingly long engagement ranges and heavier secondary batteries of the last pre-dreadnoughts; Japan and the United States had designed ships with a similar armament before Dreadnought, but were unable to complete them before the British ship. It was felt that because of the longer distances at which battles could be fought, only the largest guns were effective in battle, and by mounting more 12-inch guns Dreadnought was two to three times more effective in combat than an existing battleship.

The armament of the new breed of ships was not their only crucial advantage. Dreadnought used steam turbines for propulsion, giving her a top speed of 21 knots, against the 18 knots typical of the pre-dreadnought battleships. Able both to outgun and outmaneuver their opponents, the dreadnought battleships decisively outclassed earlier battleship designs.

Nevertheless, pre-dreadnoughts continued in active service and saw significant combat use even when obsolete. Dreadnoughts and battlecruisers were believed vital for the decisive naval battles which at the time all nations expected, hence they were jealously guarded against the risk of damage by mines or submarine attack, and kept close to home as much as possible. The obsolescence and consequent expendability of the pre-dreadnoughts meant that they could be deployed into more dangerous situations and more far-flung areas.

World War I

During World War I, a large number of pre-dreadnoughts remained in service. The advances in machinery and armament meant that a pre-dreadnought was not necessarily the equal of even a modern armoured cruiser, and was totally outclassed by a modern dreadnought battleship or battlecruiser. Nevertheless, the pre-dreadnought played a major role in the war.

This was first illustrated in the skirmishes between British and German navies around South America in 1914. While two German cruisers menaced British shipping, the Admiralty insisted that no battlecruisers could be spared from the main fleet and sent to the other side of the world to deal with them. Instead the British dispatched a pre-dreadnought of 1896 vintage, HMS Canopus (1897). Intended to stiffen the British cruisers in the area, in fact her slow speed meant that she was left behind at the disastrous Battle of Coronel. Canopus redeemed herself at the Battle of the Falkland Islands, but only when grounded to act as a harbour-defence vessel; she fired at extreme range (13500 yd) on the German cruiser SMS Gneisenau, and while the only hit was from an inert practice shell which had been left loaded from the previous night (the "live" shells of the salvo broke up on contact with water; one inert shell ricocheted into one of Gneisenau's funnels), this certainly deterred Gneisenau. The subsequent battle was decided by the two Invincible-class battlecruisers which had been dispatched after Coronel. This appears to have been the only meaningful engagement of an enemy ship by a British pre-dreadnought.

In the Black Sea five Russian pre-dreadnoughts saw brief action against the Ottoman battlecruiser Yavuz during the Battle of Cape Sarych in November 1914.

The principle that disposable pre-dreadnoughts could be used where no modern ship could be risked was affirmed by British, French and German navies in subsidiary theatres of war. The German navy used its pre-dreadnoughts frequently in the Baltic campaign. However, the largest number of pre-dreadnoughts was engaged at the Gallipoli campaign. Twelve British and French pre-dreadnoughts formed the bulk of the force which attempted to "force the Dardanelles" in March 1915. The role of the pre-dreadnoughts was to support the brand-new dreadnought HMS Queen Elizabeth (1913) engaging the Turkish shore defences. Three of the pre-dreadnoughts were sunk by mines, and several more badly damaged. However, it was not the damage to the pre-dreadnoughts which led to the operation being called off. The two battlecruisers were also damaged; since Queen Elizabeth could not be risked in the minefield, and the pre-dreadnoughts would be unable to deal with the Turkish battlecruiser lurking on the other side of the straits, the operation had failed. Pre-dreadnoughts were also used to support the Gallipoli landings, with the loss of three more: HMS Goliath (1898), HMS Triumph (1903) and HMS Majestic (1895).

A squadron of German pre-dreadnoughts was present at the Battle of Jutland in 1916; German sailors called them the "five-minute ships", which was the amount of time they were expected to survive in a pitched battle. In spite of their limitations, the pre-dreadnought squadron played a useful role. As the German fleet disengaged from the battle, the pre-dreadnoughts risked themselves by turning on the British battlefleet as dark set. Nevertheless, only one of the pre-dreadnoughts was sunk: SMS Pommern went down in the confused night action as the battlefleets disengaged.

Following the November 1918 Armistice, the U.S. Navy converted fifteen older battleships, eight armoured cruisers and two larger protected cruisers for temporary service as transports. These ships made one to six trans-Atlantic round-trips each, bringing home a total of more than 145,000 passengers.

World War II

After World War I, most battleships, dreadnought and pre-dreadnought alike, were disarmed under the terms of the Washington Naval Treaty. Largely this meant the ships being broken up for scrap; others were destroyed in target practice or relegated to training and supply duties. One, JAPANESE BATTLESHIP Mikasa, was given a special exemption to the Washington Treaty and was maintained as a museum and memorial ship.

Germany, which lost most of its fleet under the terms of the Versailles treaty, was allowed to keep eight pre-dreadnoughts (of which only six could be in active service at any one time) which were counted as armoured coast-defence ships; two of these were still in use at the beginning of World War II. One of these, SMS Schleswig-Holstein, shelled the Polish Westerplatte peninsula, opening the German invasion of Poland and firing the first shots of the Second World War. Schleswig-Holstein served for most of the war as a training ship; she was sunk while under refit in December 1944, and broken up in situ in January 1945. The other, SMS Schlesien, was mined and then scuttled in March 1945.

A number of the inactive or disarmed pre-dreadnoughts were nevertheless sunk in action during World War II, such as the Greek pre-dreadnoughts GREEK BATTLESHIP Kilkis and GREEK BATTLESHIP Lemnos, bought from the U.S. Navy in 1914. While neither of the ships was in active service, they were both sunk by German dive bombers after the German invasion in 1941. In the Pacific, the U.S. Navy submarine USS Salmon (SS-182) sank the disarmed Japanese pre-dreadnought JAPANESE BATTLESHIP Asahi in May 1942. A veteran of the Battle of Tsushima, she was serving as a repair ship.

Post World War II
No pre-dreadnoughts served post–World War II as armed ships; the last serving pre-dreadnought was the former SMS Hessen, which was used as a target ship by the Soviet Union into the early 1960s as the Tsel. The hull of the former USS Kearsarge (BB-5) served as a crane ship from 1920 until its scrapping in 1955. The hulk of the ex-USS Oregon (BB-3) was used as an ammunition barge at Guam until 1948, after which she was scrapped in 1956.

Survivors

There is only one pre-dreadnought preserved today: the Imperial Japanese Navy's flagship at the Battle of Tsushima, Mikasa, which is now located in Yokosuka, where she has been a museum ship since 1925.

title: Pre-dreadnought battleship


text:
Richard Temple-Nugent-Brydges-Chandos-Grenville, 3rd Duke of Buckingham and Chandos

Richard Plantagenet Campbell Temple-Nugent-Brydges-Chandos-Grenville, 3rd Duke of Buckingham and Chandos, (10 September 1823 – 26 March 1889), styled Earl Temple until 1839 and Marquess of Chandos from 1839 to 1861, was a British soldier, politician and administrator of the 19th century. He was a close friend and subordinate of Benjamin Disraeli and served as the secretary of state for the colonies from 1867 to 1868 and governor of Madras from 1875 to 1880.

Buckingham was the only son of Richard Temple-Grenville, 2nd Duke of Buckingham and Chandos, and was educated at Eton and Christ Church, Oxford. He joined the British Army, eventually rising to become a colonel. Buckingham entered politics, as Lord Chandos, in 1846 when he was elected unopposed from Buckinghamshire as a candidate of the Conservative Party. Buckingham served as a member of Parliament from 1846 to 1857, when he resigned. He contested a re-election in 1859, but lost. Buckingham served in various political offices during his tenure.

In March 1867, he was appointed Secretary of State for the Colonies and served until December 1868. He also served as governor of Madras from 1875 to 1880. As governor, he handled the relief measures for the victims of the Great Famine of 1876–1878. Buckingham also served as Lord of the Treasury, Keeper of the Privy Seal of the Prince of Wales, Deputy Warden of the Stannaries, Deputy Lieutenant of Buckinghamshire, Chairman of the London and North-Western Railway, member of the Imperial Privy Council, Lord President of the Council and chairman of the committees in the House of Lords. He died in 1889 at the age of 65.

Background and education
Buckingham was the second child and only son of Richard, 2nd Duke of Buckingham and Chandos, and his wife Lady Mary, younger daughter of John Campbell, 4th Earl of Breadalbane and Holland (later the 1st Marquess of Breadalbane). His sister, Lady Anna Eliza Mary Gore-Langton, was a women's rights campaigner. As his father's son and heir apparent, he was styled Earl Temple from birth. He was 15 years of age when his paternal grandfather died and his father became the 2nd Duke of Buckingham and Chandos. From this time, he was styled Marquess of Chandos until he succeeded his father as Duke.

Upon his father's death in 1861, his titles were Duke of Buckingham and Chandos, Marquess of Chandos, and Earl Temple of Stowe in the Peerage of the United Kingdom; Marquess of Buckingham, Earl Temple, Viscount and Baron Cobham in the Peerage of Great Britain; and Earl Nugent in the Peerage of Ireland. In 1868, he was also recognised by the House of Lords as Lord Kinloss in the Peerage of Scotland. He inherited 10,500 acres, mostly in Buckingham.

The young Lord Temple, later Lord Chandos, attended Eton until 1841 and graduated from Christ Church, Oxford, from which he later received an honorary degree of D.C.L. Two years after graduation, Lord Chandos (as he then was) was commissioned a Lieutenant in the Royal Buckinghamshire Yeomanry and he would eventually become Honorary Colonel of that regiment. He was also Hon. Colonel of the 1st Administrative Battalion, Middlesex Artillery Volunteers and later of the City of London Artillery.

Early career

In 1846, Buckingham, as the Marquess of Chandos, entered Parliament as Conservative MP for Buckinghamshire, and remained as an unopposed MP until 1857. The young Lord Chandos was appointed a deputy lieutenant for Oxfordshire on 3 February 1846, Hampshire on 17 February, and Northamptonshire on 29 May.

In 1852, he entered Lord Derby's administration as a Lord of the Treasury, a position he held for exactly ten months. That year, he was also appointed Keeper of the Privy Seal of the Prince of Wales, Deputy Warden of the Stannaries, deputy lieutenant of Buckinghamshire, and chairman of the London and North-Western Railway. In 1857, he resigned as MP for Buckinghamshire and did not stand for re-election. In 1861, he succeeded his father as Duke of Buckingham and Chandos (and in various other titles across four Peerages) and took his seat in the House of Lords. In the 1860s he was chairman of the London Pneumatic Despatch Company.

Buckingham's political career was stagnant until 1866, when he was appointed to the Privy Council and became Lord Derby's Lord President of the Council. He served as Lord President of the Council until 8 March 1867, when he succeeded Lord Carnarvon as Secretary of State for the Colonies.

As Secretary of State for the Colonies
Buckingham was appointed Secretary of State for the Colonies when Lord Carnarvon resigned in March 1867 over the Reform Bill and served from 8 March 1867 to 1 December 1868. During this period, he was also appointed Lord Lieutenant of Buckinghamshire. As Secretary of State for the Colonies. Buckingham had to deal with the British North America Act. He also attracted controversy over his dispute with Bishop Colenso of Natal. Buckingham's tenure ended in December 1868 when the Conservative Party ministry of Benjamin Disraeli resigned. He was succeeded as Colonial Secretary by Lord Granville.

On 21 July 1868, the House of Lords recognised him as the 10th Lord Kinloss in the Peerage of Scotland, which had been dormant since the death of the 6th Lord Kinloss, his three-times great-grandfather Charles Bruce, 4th Earl of Elgin, in 1747. Through the House of Lords ruling, Buckingham's father was recognised posthumously as de jure 9th Lord Kinloss, his maternal grandmother Lady Anna Brydges as de jure 8th Lady Kinloss, and his great-grandfather James Brydges, 3rd Duke of Chandos as de jure 7th Lord Kinloss. Though the lordship was the most minor of Buckingham's many titles, it was the only one that could be inherited by his daughters, and he established his right to it at a time when the likelihood emerged that he would leave no male heir.

Governor of Madras

When the Conservative Party was re-elected to power in the United Kingdom in 1874 and Disraeli became the Prime Minister once again, Buckingham was appointed Governor of the Madras Presidency, British India. Buckingham moved to Madras and took his seat on 23 November 1875.

Buckingham served as the governor of Madras from 1875 to 1880. His tenure was plagued by deteriorating socio-economic and health conditions. In 1876, the Great Famine of 1876–78 broke out in Madras Presidency. By August 1877, the famine had spread all over the Presidency and over 18 million people were affected. To make matters worse, the rains failed in parts of Madras and Mysore. Large quantities of grain were shipped from Bengal to Madras port, and through his efforts, famine relief was distributed to 839,000 people in the Madras districts, besides 160,000 in the Bombay Districts and 151,000 in the Mysore districts.

The Governor appealed to the principal cities of England, Scotland, Ireland and India for assistance. At Buckingham's suggestion, the Lord Mayor of London collected relief funds of up to £475,000 in 1877 (£ as of 2024). Though the famine eventually came to an end in 1878, the issue had far-reaching effects.

As a part of the famine relief work, Buckingham had commenced the construction of a navigation channel between Madras city and the northern part of the Madras Presidency so that transportation of supplies to the interior in cases of emergency would be easy. More than 715,000 people were employed as labourers in Madras to assist with the relief work. Opened in 1878, this canal was named after Buckingham as Buckingham Canal. Buckingham Street in Penang, Malaysia was also named after him by the Tamil labourers who were brought there during the British colonial period.

Displeasure of the tribes of the northern part of the Presidency over the stringent taxation schemes of the British government erupted in the form of a major rebellion in 1879. The rebellion was eventually suppressed through a joint operation of the Madras police and army and the Hyderabad army, and the captured prisoners were sent to the Andamans. Many of the stringent taxation laws were repealed.

On 30 August 1880, William Patrick Adam was appointed Governor of Madras and he succeeded Buckingham in December 1880.

Later life and death

In May 1886, Buckingham succeeded Lord Redesdale as Chairman of Committees in the House of Lords. He made few speeches in the House of Lords and succeeded in paying off most of his father's debts. Gradually, towards the later part of his life his financial situation improved and by 1883, he owned 10,482 acre of land with a total value of £18,080.

Buckingham died in March 1889, aged 65, from diabetes at Chandos House, London. His illness was unexpected and not originally thought to be serious; the House of Lords postponed voting on several bills until he recovered. Within a week, however, his illness proved fatal, despite the efforts of Dr. Henry Walter Kiallmark, the family physician, and Sir James Paget, who was called in to assist.

The duke was buried at the family vault in the church at Wotton House, Buckinghamshire.

With no male issue, the dukedom and marquessate of Buckingham and Chandos and the Earldom of Temple became extinct. Several of his other titles survived due to available heirs: his nephew William Gore-Langton succeeded him in 1892 as fourth Earl Temple of Stowe, which was created with a special remainder; his eldest daughter, Lady Mary, succeeded him in the Scottish lordship of Kinloss, which can be held by females, as Lady Kinloss; and his distant relative Charles Lyttelton succeeded him as eighth Viscount Cobham.

Family
Buckingham married firstly Caroline Harvey, daughter of Robert Harvey of Langley Park, Sheriff of Buckinghamshire, and sister of Sir Robert Harvey, 1st Baronet of Langley Park, in 1851. They had three daughters:

 * Mary Morgan-Grenville, 11th Lady Kinloss (1852–1944)
 * Lady Anne (1853–1890)
 * Lady Caroline Jemima Elizabeth (1858–1946)

Caroline, Duchess of Buckingham and Chandos, died in February 1874.

Buckingham married, secondly, Alice Graham-Montgomery, daughter of Sir Graham Graham-Montgomery, 3rd Baronet, in 1885. Born in 1848, she was 25 years younger than him. In 1897, she was one of the guests at the Duchess of Devonshire's Diamond Jubilee Costume Ball. There were no children from this marriage. Widowed in 1889, Alice, Dowager Duchess of Buckingham and Chandos, married the 1st Earl Egerton in 1894. She died in 1931, aged 83.


text:
Talk:Wild Hunt

What does this mean?
"One tradition maintains that Odin did not travel further up than an ox wears his yoke, so if Odin was hunting, it was safest to throw oneself onto the ground in order to avoid being hit" - this makes no sense. Poihths (talk) 22:58, 19 January 2022 (UTC)
 * I understand it as "Odin rides at low height, duck!" is that it? --ReyHahn (talk) 13:42, 20 January 2022 (UTC)

Yes. Yoke is about 1.5-2.0m above the ground 85.148.213.144 (talk) 08:22, 23 February 2022 (UTC)

What were they hunting
The article should make a mention of what is being hunted 85.148.213.144 (talk) 08:23, 23 February 2022 (UTC)
 * Depends on the tale. Mythical creatures, people, peasants... This was a mythical danger to be avoided in case _you_ become the target - Skysmith (talk) 13:12, 23 February 2022 (UTC)

I lost my wife 😭😭
Heathcliff 2A02:9130:FD1E:6CA4:17E3:8332:489E:150 (talk) 17:59, 19 July 2024 (UTC)

title: Talk:Wild Hunt


text:
Challengers of the Unknown

The Challengers of the Unknown is a fictional group of adventurers appearing in comic books published by DC Comics. The quartet of adventurers explored paranormal occurrences while facing several fantastic menaces.

The characters' provenance is uncertain. Various sources credit the group as the sole creation of artist and storyteller Jack Kirby, a co-creation with writer Dave Wood or a co-creation with Kirby's former partner Joe Simon. Following the end of the Challengers comic, DC has revived the characters in different incarnations over the years.

Some have claimed that Kirby reworked the basic concept of the series with Stan Lee in 1961 to create The Fantastic Four, the first creation that marked the rise of Marvel Comics.

Publication history
The adventuring quartet the Challengers of the Unknown debuted in Showcase #6 (February 1957), in an uncredited story attributed to Jack Kirby for art and to Kirby and Dick Wood for script, under editor Jack Schiff.

The series continued in the bimonthly Showcase for three more appearances (#7, 11–12, April 1957, December 1957 – February 1958) then moved to its own title, starting with issue #1 (May 1958). Kirby moved on after issue #8 (July 1959), with Bob Brown succeeding him as artist. The title continued through issue #75 (September 1970), followed by two reprint issues. The series was canceled with issue #77 in 1971 (January 1971). In 1973, three reprint issues were published (#78–80). The team’s lineup was briefly enhanced with the inclusion of the paranormal sensitive Corrina Stark toward the end of this run.

Revivals
The Challengers had a short-lived 1976–77 revival in Super-Team Family #8–10. The group then returned to its own title continuing the number with #81. During this period, they were joined by Deadman and Swamp Thing, and associate June Robbins got a uniform and official status. No explanation was given for Corinna Stark's departure, nor June's joining the team. The revived series was canceled with issue #87 in 1978. Adventure Comics Digest #493–497 (1982) featured an expanded version of the team's origin.

The Challengers returned in a limited series, Challengers of the Unknown (vol. 2) (1991), by writer Jeph Loeb and artist Tim Sale. It ran eight issues and was reprinted in trade paperback as Challengers of the Unknown Must Die! (2004). This series depicted the Challengers in middle age, breaking up after a tragic accident and coming back together as a team. Loeb hoped for a monthly title, and planned at least a second limited series, but neither volume materialized. Elements of this revival later appeared in several Superboy stories around the turn of the millennium, as a second, unrelated group had a title in the late 1990s as part of the Weirdoverse line.

In 2000, DC published a one-shot, Silver Age: Challengers of the Unknown, done in the style of the original Silver Age of Comic Books Challengers.

Fictional group history
The roster included Ace Morgan, Prof Haley, Rocky Davis and Red Ryan, with their occasional companion June Robbins. Ryan was killed and briefly replaced by his younger brother Marty, a pop singer who used the anagram ID of Tino Manarry. Red Ryan returned from the dead and Tino was written out after suffering an injury that left him blind. Toward the end of the original series, a woman with an occult background named Corinna Stark acted as a fifth member of the team.

Countdown to Final Crisis
Prepublication solicitations for various Countdown to Final Crisis tie-ins referred to the group of Donna Troy, Jason Todd, Kyle Rayner, and "Bob" (a nefarious, renegade "purist" Monitor), as "Challengers from Beyond". This group went on a quest through the newly formed multiverse to find Ray Palmer, whom Bob claimed was essential to the survival of the universe. Eventually the Earth heroes were betrayed by Bob, who sought to kill Palmer, rather than protect him or acquire his aid. Palmer, Troy, Todd, and Rayner found themselves involved in a war between the Monitors and Monarch's forces. Later they traveled to Apokolips, where they teamed up with Jimmy Olsen, Forager, Karate Kid and Triplicate Girl. After returning to Earth, Troy, Rayner, Forager, and Palmer decided to team up again. They traveled to the Monitors' headquarters, where they informed the shocked beings that they would be watching over them as a sort of interdimensional border guards.

The Brave and the Bold
The 2007 revival of The Brave and the Bold series features a storyline involving the Challengers. Destiny of the Endless reveals to Supergirl and Lobo that his Book of Destiny has changed because there appeared to be men who existed, but were not recorded in the book, and their undocumented actions made the book unreliable. Destiny cast the book away, and it was eventually recovered by Batman and Green Lantern with the help of the Challengers, the men in question, who become the new holders of the book. Destiny later reclaims the book.

Leslie "Rocky" Davis appears regularly in Doom Patrol, in which he serves as something of a counselor to the members of that team, and resides on Oolong Island.

Post-Flashpoint
In 2011, the DC Universe was dramatically altered, giving very different back stories to many of its heroes and villains. This version of the Challengers incorporates elements of the original and 1990s lineups.

The Challengers were formed for a reality television contest, when several notable people were assembled by archaeologist presenter Clay Brody for his "Challengers" program. Clay, the contestants, producer June, and pilots Ace and Maverick, were lost in the Himalayas when their plane crashed under mysterious circumstances. All but one of them showed up weeks later, remembering a recuperation in Nanda Parbat, in which the city's elder told them to beware the unknown, but also to challenge it. Returning to civilization, the group found a talisman that had led Clay to pick them, and a note explaining that it was one of a set.

The Challengers program was retooled to take advantage of the quest. With their home base on a Metropolis soundstage dubbed "Challengers Mountain", the group sought out the talismans in far-flung corners of the world, usually accompanied by some oddity, like warrior statues or giant-ant-spewing portals. Their greatest initial challenge came when in a short period their show was cancelled and they were attacked by their dead friend, "Ace" the pilot. Though he killed two of them, they managed to defeat him, and the survivors vowed to find the rest of the talismans and save the world.

The original Challengers Prof, Ace, Red, and Rocky were on a mission on an Earth in the Dark Multiverse when Prof was badly wounded. He figured out how to use the dark energy to heal himself. In doing so he inadvertently sent his dark multiverse counterpart to the multiverse. The Dark Prof created a new Challengers that he could use to collect the remains of an ancient god whose remains were flung through time and space when the Source Wall was destroyed. The Dark Prof recruits Trina Alvarez, Moses Barber, Krunch, and Bethany Hopkins as the most current incarnation of the team. They soon discover his evil intentions and send him back to the Dark Multiverse, saving Ace, Red, Rocky and Prof in the process.

Alternative versions
DC published two other series, also titled Challengers of the Unknown, featuring the original Challengers' concept combined with a new set of characters.

The Challengers were revamped by writer Steven Grant in vol. 3 (1997), which had a totally new group of characters and was one of four series making up the Weirdoverse group of titles. This ongoing series ran 18 issues, through 1998. This team of paranormal investigators met the original Challengers and even had Rocky agree to advise them.

One more revamp was done by Howard Chaykin in a six-issue miniseries (vol.  4, 2004–2005). This series had another new group of characters and was entirely unrelated to the previous two incarnations.

Fictional character biographies
When acquaintances miraculously survive a plane crash unscathed, they conclude that since they are "living on borrowed time" they should band together for hazardous adventures. The four—pilot Kyle "Ace" Morgan, daredevil Matthew "Red" Ryan, strong and slow-witted Leslie "Rocky" Davis, and scientist Walter Mark "Prof" Haley—became the Challengers of the Unknown.

Soon famous, the Challengers accept many "unknown challenges" from The Pentagon, mad scientists, and people with a problem. Over time the "Challs" establish the hollowed-out Challengers Mountain as headquarters. Later they adopt an hourglass logo to symbolize time running out. They encounter genies, common and sophisticated thieves, rocs, aliens and robots good and bad. Their adventures later veer toward superheroics, and take in everything from occult menaces to Bermuda Triangle mysteries. The Challengers travel through space, time, and other dimensions. They encounter the likes of the Doom Patrol, Deadman, Swamp Thing, Jonny Double, and the Sea Devils, with whom they fight the criminal group Scorpio. June Robbins, a computer genius and archaeologist, joined the Challengers for many adventures as an "honorary" or "girl" Challenger. June first officially joins the team after the rogue robot 'Ultivac' seemingly kills one of the original Challengers. However that man returns thanks to heroic efforts of modern medical science.

When Red is killed, a teen rock star/engineering genius immediately wages a vendetta against the three-man team. "Tino Mannaray" turns out to be Martin Ryan, Red's kid brother, who blames the team for his death. Red eventually returns; though blown up, he had been dosed with shape-changing Liquid Light and rendered amnesiac, but still nearly conquered the Pacific as a Tiki god.

As the team's challenges become more occult, Red's brother Tino is blinded. Red donates an eye to his brother and dons an eye patch. Eventually Red receives an eye transplant. Prof becomes possessed by an evil spirit and is shot by a villain. While he recovers, Corinna Stark, a mysterious blonde with mystical knowledge, invites herself onto the team. The Challengers fight occult alien-monsters in backwoods villages and dark dreams, and Rocky and Red fight for Corinna's affection.

Challengerville
The Challs are later semi-retired, their mountain a theme park, and their adventures disregarded as cooked-up articles in a tabloid, The Tattletale. The nearby town has renamed itself Challengerville, managing to thrive on the team's name. A cosmic entity, which prides itself as "the personification of all evil", influences the entity Multi-Man to blow up the mountain. The town is destroyed. Hundreds die, including, seemingly, Prof and June. The surviving Challengers are placed on trial, but eventually freed with the testimony of Superman. They are, however, ordered to disband.

A tabloid reporter, Moffet, becomes involved with the group after several unexplained incidents. Moffet begins to piece together many seemingly unrelated massacres. Red became a violent, vigilante mercenary. Ace becomes an addled mystic, losing new-found friends due to inattention and incompetence. Rocky becomes lost in a life of luxury and ends up in an insane asylum.

Eventually the three reunite, and with Moffet's aid, find a strange portal near what was once Challengerville. They discover Prof and June, pregnant, "alive" in a strange "phantom zone". The dark demon confronts them and the final battle comes down to Moffet and a neutron bomb. The decision to attack is literally taken out of his hands by Multi-Man, who sacrifices himself to destroy the demon. "The New Challengers of the Unknown", including ghostly Prof and June, were poised to take on menaces in the dark corners of the world.

Later, four new Challengers pursue X-Files-like horrors. They are Clay Brody, NASCAR driver; Brenda Ruskin, physicist; Kenn Kawa, radical games designer; and Marlon Corbet, commercial pilot, who also miraculously survived a plane crash. They stopped sacrificial wackos, drug-juiced zombies, vengeful ghosts, Amazon cults, Lovecraftian monsters, mass suicides, humming buildings, and other oddities. They were advised by Rocky Davis, older and grayer and alone. It was eventually revealed that the original Challengers were dematerialized by a mad scientist's ray-weapon. The same ray caused both plane crashes, as well as others. Soon the original Challs reappeared, helped the young Challs defeat the madman, then walked back into oblivion (minus a wounded Rocky) to shut down a runaway Tesla field. The young Challengers vowed to fight on.

Superboy discovers the missing Challengers—Ace, Red, Prof, and June—in Hypertime. The team was waging guerrilla war against Black Zero (a Superboy variant). With Black Zero defeated, the team returns to Earth, but loses Red along the way. Reunited with Rocky in Metropolis, hosted by Rip Hunter, the original Challengers vow to explore Hypertime, "the greatest unknown", to find Red.

Two Challengers partake in Infinite Crisis. Rocky Davis and Prof Haley help stem the escape of prisoners from Blackgate Prison. Rocky fights in the Battle of Metropolis. He is one of dozens of heroes fighting the opposing army of the Secret Society of Super Villains. The Society is ultimately defeated.

Later, on a world without superheroes, a blogger, a hip hop artist, an eco-terrorist, and two others discovers they'd been genetically enhanced and chip-programmed to be soldier-pawns by the Hegemony, a cabal of billionaires who secretly run that world. Made slaves on a Moon base, three Challengers blow up the base, escape to Earth, and declare war on the Hegemony until (like the obliquely mentioned earlier Challengers) their "borrowed time" runs out.

Other versions
The Challengers make a brief appearance in the Elseworlds miniseries Conjurers, set in an alternate DCU where magic is a part of mainstream society. These are the "Volume 3" Challengers, but given the nicknames of the originals: Kenn is "Prof", Clay is "Rocky", Brenda is "Red", and Marlon is "Ace". Since Kenn was always shown as the most "mystical" of the new Challs, it makes sense that he would be "Prof" in a magical universe, rather than Brenda, the team's scientist.

During Superboy's trip through Hypertime, referenced above, he briefly visits an Elseworld in which the Challengers were himself, Ace, Guardian, and Dubbilex. The June who arrives in the DCU at the end of that story is also an Elseworlds version, coming from a universe where she was a full Challenger from the beginning. She was apparently exchanged with the June of the main timeline when she was struck by Hypertime energies.

The Challengers also made brief appearances in JLA: Another Nail (when all time periods meld together) and The Adventures of Superman Annual #7 (as part of a strikeforce of non-powered heroes).

They were prominently featured in Darwyn Cooke's DC: The New Frontier miniseries (2003–2004). Various members were essential in many battles against menaces that arose throughout the series.

In the 1996 crossover series Amalgam Comics, the Challengers were merged with the Fantastic Four to become Challengers of the Fantastic.

Villains
The Challengers of the Unknown have faced an array of villains:
 * Amenothoth – an ancient Egyptian villain.
 * Brainiex – sentient computer/spaceship, allied with Villo.
 * Burt Langdon – a criminal who competed against the Challengers of the Unknown to obtain a wizard's deadly device.
 * Chang – an Asian mastermind.
 * Dakyab – an alien tyrant.
 * Dane Cary – a criminal that was sabotaging the filming of Connie Baylor's latest movie.
 * Darius Tiko – a scientist who discovers a time cube that lets him travel to the past and future.
 * Dekkar – a villain who once used a machine to steal the memories of the Challengers of the Unknown.
 * Dimension Man (D-Man) – a criminal scientist who had the ability to teleport and access other dimensions.
 * Dr. Fenton – a scientist who once kidnapped June Robbins.
 * Dr. Heathcliff Monroe – a scientist who worshipped M'nagalah.
 * Dr. Heller – a Neo-Fascist who the Challengers of the Unknown encounter on a deserted island.
 * Dr. Manning – a scientist who ends up turned into a giant, super-strong, rampaging caveman.
 * FX-1 – a robot that goes independent and ends up going on a rampage when struck by lightning.
 * Gargoyle – "Gary Doyle" is a roof-climbing villain who meets a blind girl and planned to pay for her surgery through whatever way he can.
 * General Tolek – a Tyran who led his kind to invade Earth.
 * Gurk – a criminal collector that once hired Multi-Man to help him find three pieces of a golden turtle statuette.
 * Hillary Mycroft – a criminal who sought to reassemble a sorcerer's apparatus.
 * Iron Dictator – an other-dimensional version of Adolf Hitler recruited by the Dimension Man.
 * Jacquard – a criminal that once challenged the Challengers of the Unknown.
 * Karnak – a criminal who used potions to create monsters.
 * Korba – a "man without a country" who enslaves people on an island to build his "world".
 * Krager – a criminal mastermind with a hook for a left hand.
 * Kubagy – an alien criminal who came to Earth to steal its chlorine to power his robot.
 * League of Challenger-Haters – a group of enemies that each fought the Challengers of the Unknown before joining as this group.
 * Drabny – a villain who steals inventions from the future to take over the present. He was later a member of the League of Challenger-Haters.
 * Kra the Living Robot – a tyrannical robot who enslaved the planet Zuna. He was later a member of the League of Challenger-Haters.
 * Multi-Man – a supervillain who gains a different form every time he dies. He was later the founder of the League of Challenger-Haters.
 * Multi-Woman – a giant robot created by Multi-Man. A second version of her later appeared as a member of the League of Challenger-Haters.
 * Villo – the "world's vilest villain".
 * Volcano Man – a lava monster. He was later a member of the League of Challenge-Haters.
 * Legion of the Weird
 * Malvolio – a criminal who possesses an ancient genie named Ahmed.
 * Mastermind – an Earth criminal who cons Cosmo's alien master into believing that the Challengers are controlling Cosmo's mind and forcing him to use his powers for evil purposes.
 * Morlean – a sorcerer who was the first villain the Challengers of the Unknown encountered.
 * Mr. Dimension – a vagrant who stole a dimensional weapon from a timeship from the far future.
 * Mr. Murlin – an alchemist that unleashed a plague that turns ordinary humans into violent zombies.
 * Mr. Tic-Tac-Toe – Dr. Bradford is a criminal who uses traps with a tic-tac-toe motif.
 * Neutro – Starrett is an element-transmuting villain.
 * Olan Tagorian – a criminal scientist whose machine can teleport monsters from other dimensions.
 * Ooze – Killer Stark was accidentally changed into the Ooze during his encounter with the Challengers of the Unknown.
 * Power Man – an energy-absorbing villain.
 * Raymond – a robot that was given to the Challengers of the Unknown as a gift, but had ulterior motives.
 * Roc – a criminal who obtained a mind-over-matter machine.
 * Roney – a criminal who obtained a stone that enables him to control two creatures.
 * Seekeenakee – an incarnate stone "god" whose worshipers want to take over the world. This was actually Red Ryan's transformed appearance.
 * Seth Gross – a wicked magician.
 * Sir Rodford – a criminal who lives in a world within a mirage.
 * Suboku – an alien who tricks the Challengers of the Unknown into doing things that would help him in his invasion.
 * Tartan – an alien ringmaster who once captured the Challengers of the Unknown for his intergalactic circus.
 * Torbert – a criminal who stole a "life liquid" from an ages-old pharaoh.
 * Tukamenon – an ancient mummy that fought the Challengers of Evil on behalf of the Legion of the Weird.
 * Ultivac – a giant computer robot that was built by an ex-Nazi scientist.
 * Volcano Men – anthropomorphic giants made of fiery lava.
 * Wizard Welles – a criminal that once enlarged Rocky's cranium
 * Zardok – a criminal mystic who gained mind-over-matter powers from a meteorite.
 * Zarxes – a dimensional villain who plotted to conquer Earth.
 * Zog – an alien criminal.

Television

 * The Challengers of the Unknown appear in Batman: The Brave and the Bold, with Walter Mark "Prof" Haley voiced by Armin Shimerman, Matthew "Red" Ryan voiced by Ioan Gruffudd, Kyle "Ace" Morgan voiced by J.K. Simmons, and Leslie "Rocky" Davis voiced by James Arnold Taylor.
 * The Challengers of the Unknown appear in the Teen Titans Go! episode "TV Knight 4".

Film

 * The Challengers of the Unknown appear in Justice League: The New Frontier, with Kyle "Ace" Morgan voiced by John Heard while the other members are silent.
 * The Challengers of the Unknown appear in Teen Titans Go! To the Movies, with Kyle "Ace" Morgan voiced by Dave Stone while the other members are silent.

Miscellaneous

 * A parody of the Challengers of the Unknown called the "Explorers of the Unknown" appear in Archie Comics.
 * The Challengers of the Unknown appear in a self-titled novel penned by Ron Goulart. (Dell Books, ISBN 0-440-11337-7)
 * The Challengers of the Unknown are referenced in The New Pornographers' song "Challengers".

Awards
The 1950–60s series won the 1967 Alley Awards for Best Non-Super-Powered Group Title and Best Normal Adventure Group.

title: Challengers of the Unknown