King Arthur is an important figure in the mythology of Great Britain, where he appears as the ideal of kingship both in war and peace. He is the central character in the cycle of legends known as the Matter of Britain. There is disagreement about whether Arthur, or a model for him, ever actually existed. In the earliest mentions and in Welsh texts, he is never given the title 'King'. An early text refer to him as a dux bellorum ('war leader'), and medieval Welsh texts often call him ameraudur ('emperor'; the word is borrowed from the Latin imperator, which could also mean 'war leader').
Main article: Historical basis for King Arthur
The historicity of the Arthur of legend has long been debated by scholars. One school of thought believes that Arthur had no historical existence.  Some hold that he originally was a half-forgotten Celtic deity that devolved into a personage (citing sometimes a supposed change of the sea-god Lir into King Lear). Supporters of this theory often link it to the Welsh etymology of Arthur's name as derived from 'bear', proposing bear gods named Artos or Artio as the precedent for the legend, but these particular deities are known to have been worshipped by the continental Celts, not the Britons.
Another view holds that Arthur was a real person. Though some theories suggest he was a Roman or pre-Roman character, by most theories, and in line with the traditional cycle of legends, he was a Romano-British leader fighting against the invading Anglo-Saxons sometime in the late 5th century to early 6th century. The late historian John Morris made the alleged reign of Arthur at the turn of the 5th century the organising principle of his history of sub-Roman Britain and Ireland under the rubric The Age of Arthur: A History of the British Isles from 350–650' (1973), even though he found little to say of an historic Arthur, save as an example of the idea of kingship, one among such contemporaries as Vortigern and Cunedda, Hengest and Coel. Recent archaeological studies show that during Arthur's alleged lifetime, the Anglo-Saxon expansions were halted until the next generation. If he existed, his power base would probably have been in the Celtic areas of Wales, Cornwall and the West Country, or the Brythonic 'Old North' which covered modern Northern England and Southern Scotland. However, controversy over the centre of his supposed power and the extent and kind of power he would have wielded continues to this day.
A number of identifiable historical figures have been suggested as the historical basis for Arthur, ranging from Lucius Artorius Castus, a Roman officer who served in Britain in the 2nd century; Roman usurper emperors like Magnus Maximus; and sub-Roman British rulers like Riothamus, Ambrosius Aurelianus, Owain Ddantgwyn and Athrwys ap Meurig.
The origin of the name Arthur is itself a matter of debate and is very much connected to the debates concerning his historicity. Some, like the above, see it as derived from the Latin 'Artorius', a Roman family name meaning 'plowman' which became 'Arturius', among other variants, in Roman inscriptions. The 5th to 6th century Welsh art (arth is a later form) means 'bear'. Thus, theories for the Welsh origin of the name Arthur have been proposed. One has art + ur, 'man of the bear' or 'bear-man', thus giving us Artur. Also, the Latin form of Arthur appears as Arturus in the earliest writings, never Artorius. The supposition of the Latin '-us' could suggest the original name was the Welsh Artur. Yet "Artorius" in its later forms when pronounced in Celtic languages could have yielded "Arthur" as well as "Arturus", both of which forms do occur in the medieval literature.
Toby C. Griffen, among others, links the name Arthur to Arcturus, the brightest star in the constellation Boötes, and the third brightest in the night sky. The word Arcturus is in Classical Latin, and would have been Arturus in the Late Latin of the 5th – 6th century. Griffen and others believe that Arthur might not be derived from a Latin original such as Artorius, as proponents of the above theories suspect, but could have been a nom de guerre used by or an epithet bestowed upon the leader who fought against the Saxons. Griffen goes on to state that the star Arturus was associated with the Great Bear. Its position in the sky, near Ursa Major, led people to call it the 'guardian of the bear', and it was regarded as the leader of the other stars in Boötes. In Welsh, the conveniently similar Artur (or possibly Arturos) meant 'bear-man'. If the man we call Arthur used Arturus (and Artur[os]) as his nom de guerre(s), its meaning(s) would have been easily understood by both the Romano-British and native British alike; a stout bear-like defender against the invaders. 
Phillips and Keatman argue for their variant of the nom de guerre theory in their book, King Arthur: The True Story. For them, the name has two components. The first would be the Welsh art meaning bear, and the second a repetition in Latin, ursus, making the original name "Artursus". According to their theory this name was a title rather than the name of a person. In any case, the name Artur and its variants was used by at least four leaders who lived after the traditional dates of Arthur’s battles, suggesting to Griffen and others that it was not used as a personal name until “the” Arthur himself did so. This idea is reinforced by the fact that Arthur's father is named Uther, phonetically similar to Arthur.
Earliest traditions of Arthur
Arthur first appears in Welsh literature. In a surviving early Welsh poem, The Gododdin (ca. AD 594), the poet Aneirin (ca. AD 535-600) writes of one of his subjects that "he fed black ravens on the ramparts, although he was no Arthur." However, it is not possible to determine if this passage is a later interpolation based on current manuscripts of the poem. The following poems attributed to Taliesin are possibly from a similarly early date: The Chair of the Sovereign, which refers to "Arthur the Blessed"; Preiddeu Annwn ("The Treasures of Annwn"), mentions "the valour of Arthur" and states "we went with Arthur in his splendid labours"; and the poem Journey to Deganwy, which contains the passage "as at the battle of Badon with Arthur, chief giver of feasts, with his tall blades red from the battle which all men remember."
Another early reference to Arthur is in the Historia Britonum, attributed to the Welsh monk Nennius, who is said to have written this compilation of early Welsh history around the year 830. In this work, Arthur is referred to as a "leader of battles" rather than as a king. Two separate sources within this compilation list twelve battles that he fought, culminating in the Battle of Mons Badonicus, where he is said to have single-handedly killed 960 men. According to the 10th century Annales Cambriae, Arthur was killed at the Battle of Camlann in AD 537.
Arthur makes appearances in a number of well known vitae ("Lives") of 6th century saints, most of them written at the monastery of Llancarfan in the 12th century. For example, in the Life of Saint Illtud, from internal evidence apparently written around 1140, Arthur is said to be a cousin of that churchman. Many of these appearances portray Arthur as a fierce warrior, and not necessarily as morally impeccable as in later romances. According to the Life of Saint Gildas (died ca. AD 570), written in the 11th century by Caradoc of Llancarfan, Arthur killed Gildas' brother Hueil, a pirate on the Isle of Man. Around 1100, Lifris of Llancarfan writes in his Life of Saint Cadoc that Arthur was bettered by Cadoc. Cadoc gave protection to a man who killed three of Arthur's soldiers, and Arthur was awarded a herd of cattle from Cadoc as wergeld for his men. Cadoc delivered them as demanded, but when Arthur took possession of the animals, they were transformed into bundles of ferns. Such episodes serve to portray a holy man besting a worldly leader. Similar incidents are described in the late medieval biographies of Carannog, Padern, Goeznovius, and Efflam.
Arthur also appears in the Welsh tale Culhwch and Olwen, a narrative that is usually associated with the Mabinogion. In that work, Culhwch visits Arthur's court to seek his help in winning the hand of Olwen. Arthur, who is described as his kinsman, agrees to the request and fulfils the demands of Olwen's giant father Ysbaddaden, which includes his hunt for the great boar Twrch Trwyth described at length by the author.
This may be related to legends where Arthur is depicted as the leader of the Wild Hunt, a folk motif that is also recorded in Brittany, France; Galicia, Spain; and Germany. Roger Sherman Loomis has listed a number of these instances (Loomis 1972). Gervase of Tilbury in the 13th century and two 15th century writers assign this role to Arthur. Gervase states that Arthur and his knights regularly hunt along an ancient trackway between Cadbury Castle and Glastonbury (which is still known as King Arthur's Causeway ), and that he with his company of riders may be seen by moonlight in the forests of Britain or Brittany or Savoy. Loomis alludes to a Scottish mention in the 16th century, and that many of these beliefs were still current in the 19th century at Cadbury Castle, and in several parts of France.
Later parts of the Trioedd Ynys Prydein, or Welsh Triads, mention Arthur and locate his court in Celliwig in Cornwall. Celliwig was identified by older Cornish antiquaries with Callington, but Rachel Bromwich, the latest editor of the Welsh Triads, matched it to Kelly Rounds, a hill fort in the Cornish parish of Egloshayle.
The Arthurian romance
The first major popularization of Arthurian legend was Geoffrey of Monmouth's fictional Historia Regum Britanniae, quite popular in medieval times, among those aristocrats wealthy enough to own books, which helped draw the attention of other writers, such as Robert Wace and Layamon, who expanded on the tales of Arthur. The date of the Historia is given as 1133 by a small proportion of experts; however, the date is more normally given as 1138, as the following quote indicates:
- Geoffrey stayed at Oxford at least until 1151 and during this period wrote his two extant works, Historia regum Britanniae (1136–1138; "History of the Kings of Britain") and Vita Merlini (ca. 1148; "The Life of Merlin").
One theory as to why Arthurian legend bloomed in this period is that the Norman Conquest of Britain in 1066 stimulated a renewed interest in British history; Edward Gibbon describes this in The Decline and Fall of the Roman Empire:
- During a period of five hundred years the tradition of his exploits was preserved, and rudely embellished, by the obscure bards of Wales and Armorica (otherwise known as Brittany), who were odious to the Saxons, and unknown to the rest of mankind. The pride and curiosity of the Norman conquerors prompted them to inquire into the ancient history of Britain; they listened with fond credulity to the tale of Arthur, and eagerly applauded the merit of a prince who had triumphed over the Saxons, their common enemies. [Chapter 38, Footnote 138]
Thus, according to Gibbon, the once obscure 500-year-old Welsh legend became more widely known (through the works of the Anglo-Norman poet Wace and others), creating a unified cultural icon under which the Norman rulers and the native Welsh could rally against their common enemy: the Saxons.
One influencing factor may have been that William the Conqueror was one-quarter Breton, and the Bretons had kept alive the legends of King Arthur brought with them when they fled Britain during the Saxon invasions five centuries earlier. Geoffrey of Monmouth was also of Breton stock. The Bretons and other British émigrés had supported William the Conqueror at the Battle of Hastings, providing a large proportion of the knights in the battle. Since the ethnic British nobility fought against the Saxons at Hastings it was inevitable that their mythology would experience a resurgence when the crown was won.
While many scholars believe that Geoffrey of Monmouth is the source for medieval interest in Arthur, at least one scholar, Roger S. Loomis, has argued that many of the tales surrounding Arthur were independently adapted from Breton oral traditions, spread through the royal and noble courts of Europe by professional storytellers known as jongleurs. The French medieval writer Chrétien de Troyes recounted tales from the Matter of Britain during the mid 12th century, as did Marie de France in her narrative lais. In any case, the later stories told by these two writers and by many others appear to be independent of what Geoffrey of Monmouth wrote.
In these Arthurian romances, which gained popularity in the 12th century, Arthur gathered the Knights of the Round Table (Lancelot, Gawain, Galahad, and others). At his court, most often held at Camelot in the later prose romances, could sometimes be found the wizard Merlin. Arthur's knights engaged in fabulous quests, the quest for the Holy Grail being perhaps the best known. Other stories from the Celtic world came to be associated with Arthur, such as the tale of Tristan and Isolde. In the late prose romances the love affair between Arthur's champion, Sir Lancelot, and the Queen, Guinevere, becomes the central reason for the collapse of the Arthurian realm.
In the romances, Arthur is killed in his last battle, the Battle of Camlann, in which he fought against the forces of Mordred. The Prose Lancelot and the later prose cyclic romances state that Mordred was also a knight of the Round Table and the child of an incestuous union between Arthur and his sister Morgause. In almost all accounts Arthur is said to have been mortally wounded, but to have been taken after the battle to Avalon, where his wounds were healed or his body buried in a chapel. Some texts refer to a return of Arthur in the future.
The Arthurian mythos spread far across the European continent. An image of Arthur and his knights attacking a castle was carved into an archivolt over the north doorway of Modena Cathedral in Italy sometime between 1099 and 1120. The surprising fact that these Italian images seem to have been carved more than a decade before the appearance of Geoffrey's "Historia" indicates how limited is our knowledge of the spread of Arthurian legend in the early Middle Ages. Also in Italy, a mosaic pavement in the cathedral of Otranto, near Bari, was made in 1165 with the unexplained depiction of Arturus Rex bearing a sceptre and riding a goat. 15th century merchants set up an Arthurian hall in his honour in Gdańsk, Poland.
Other medieval retellings of the Arthurian cycle include the works of Gottfried von Strassburg and Wolfram von Eschenbach, the anonymous Sir Gawain and the Green Knight, the anonymous stanzaic Morte Arthur, and Stricker's Daniel von Blumenthal. Thomas Malory's Le Morte d'Arthur, published in 1485, is perhaps the first modern Arthurian text. It is also the most important for the subsequent tradition in English. Malory's work is the source for Tennyson's Idylls of the King—the most popular version of the story during the 19th century. Malory is also the direct source for The Once and Future King (1958), by T.H. White, itself the source for the popular musical and film Camelot and nearly all versions of the story that have been produced since. For more about how versions of the story have influenced each other, see King Arthur in various media.
In 1191, monks of Glastonbury Abbey announced that they had found the burial site of Arthur and Guinevere. Their grave was shown to many people, and the reputed remains were moved to a new tomb in 1278. The tomb was destroyed during the Reformation, and the bones lost. The antiquary John Leland reports that he saw the cross found with the remains, and transcribed its inscription as
- Hic iacet sepvltvs inclytvs rex artvrivs in insvla avalonia — "Here lies buried the famous King Arthur in the Island of Avalon".
If Leland accurately reproduced the script of this inscription, then it can be dated to the 10th century. At least one scholar has suggested that the cross was added when Arthur's remains were transferred to the abbey. Almost all are skeptical of the discovery, as Glastonbury monks were notorious forgers.
- Hic jacet Arthurus, Rex quondam, rexque futurus — "Here lies Arthur, Former king, and future king.
Main article: Excalibur
In Robert de Boron's Merlin, Arthur obtained the throne by pulling a sword from a stone. In this account, this act could not be performed except by "the true king," meaning the divinely appointed king or true heir of Uther Pendragon. This sword is thought by many to be the famous Excalibur and the identity is made explicit in the later so-called Vulgate Merlin Continuation, part of the Lancelot-Grail cycle. However, in what is sometimes called the Post-Vulgate Merlin, Excalibur was taken from a hand rising from a lake and given to Arthur by the Lady of the Lake sometime after he began to reign. According to many sources, Arthur broke the sword pulled from the stone while fighting King Pellinore, and thus Merlin took him to retrieve Excalibur from the lake (as cited in many novels including Howard Pyle's King Arthur and His Knights, King Arthur and the Legend of Camelot, and indeed most modern Arthurian literature). In this Post-Vulgate version, the sword's blade could slice through anything, including steel, and its sheath made the wearer invincible in that the wearer could not die so long as they bore the scabbard.
Some stories say that Arthur did indeed pull the sword from the stone (Excalibur), giving him the right to be king, but accidentally killed a fellow knight with it and cast it away. Merlin told him to undertake a quest to find another blade, and it was then that Arthur received his sword from the hand in the water, and named it Excalibur, after his original sword. The first appearance of the sword named Caliburn is in Geoffrey of Monmouth, who asserted that in battle against Arthur "nought might armour avail, but that Caliburn would carve their souls from out them with their blood." ().
- List of Arthurian characters
- List of legendary kings of Britain
- Nine Worthies, of which Arthur was one
- Sites and places associated with Arthurian legend
- Asteroids 2597 Arthur and 2598 Merlin, named after the Arthurian figures
- Arthur Tudor, named after Arthur with a hope that he would restore English greatness
- Leslie Alcock. Arthur's Britain: History and Archaeology AD 367 - 634. Allen Lane, The Penguin Press. London. 1971. ISBN 0-7139-0245-0
- Chris Barber & David Pykitt. Journey to Avalon. 1993.
- Richard Barber, King Arthur in Legend and History, Boydell Press, Woodbridge 2004, ISBN 0-85115-254-6 
- Rachel Bromwich, "Concepts of Arthur", Studia Celtica, 9/10 (1976), pp.163-81.
- Ronan Coghlan, Encyclopaedia of Arthurian Legends, Element, Shaftesbury, 1991.
- David N. Dumville, "Sub-Roman Britain: History and Legend", History 62 (1977), pp. 173-92.
- Adrian Gilbert, Baram Blackett & Alan Wilson. The Holy Kingdom. 1998.
- Norma Lorre Goodrich: "King Arthur", 1986 New York/London: Franklin Watts ISBN 0-531-09701-3
- Phyllis Ann Karr: "The Arthurian Companion", 2001 Oakland: Green Knight Publishing ISBN 1-928999-13-1
- Longford, Elizabeth (Editor) "Arthur" chapter in The Oxford Book of Royal Anecdotes. 1989. Oxford University Press, Oxford & New York
- Roger S. Loomis, "The Arthurian Legend before 1139", The Romanic Review, 32 (1941), 3-38.
- Daniel Mersey. Arthur King of the Britons: From Celtic Hero To Cinema Icon. Summersdale. Chichester. 2004. ISBN 1-84024-403-8
- John Morris. "The Age of Arthur." New York: Scribner, 1973. SBN 684 13313 X
- Thomas Jones, "The Early Evolution of the Legend of Arthur", Nottingham Medieval Studies, 8 (1964), pp. 3-21.
- Derek Pearsall, Arthurian Romance: a short introduction, Blackwell, Oxford 2005 ISBN 0-631-23319-9
- Graham Phillips & Martin Keatman. King Arthur: The True Story. 1992.
- Robert Rouse and Cory Rushton, The Medieval Quest for Arthur, Tempus, Stroud, 2005 ISBN 0-7524-3343-1