The illustration on the right shows a detail of a magnificent 21-by-16-foot tapestry of King Arthur woven about 1385. The tapestry comes from a set of the "Nine Worthies," who were regarded in the late Middle Ages as the greatest military leaders of all times. Chaucer's French contemporary Eustace Deschamps wrote a ballade about them as a reproach to what he regarded as his own degenerate age. Arthur and his knights, although believed by most medieval people to be historical, are almost entirely products of legend and literature, made up by many authors writing in different genres, beginning not long after the fifth and early sixth centuries, the time when he supposedly lived, and culminating with Sir Thomas Malory's Morte Darthur in the latter part of the fifteenth century (NAEL 8, 1.439-56). The very absence of historical fact to underpin the legends about Arthur left writers of history and romance free to exploit those stories in the service of personal, political, and social agendas.

The man who inspired the Arthurian legend would have been a Briton, a leader of the Celtic people who had been part of the Roman Empire and had converted to Christianity after it became the official religion of Rome. At the time, the Britons were making a temporarily successful stand against the Anglo-Saxon invaders who had already occupied the southeastern corner of Britain. The Roman Empire was crumbling before the incursions of Germanic tribes, and by the late fifth century the Britons were cut off from Rome and forced to rely for protection on their own strength instead of on the Roman legions (NAEL 8, 1.4).

Arthur was never a "king"; he may well have been commander-in-chief of British resistance to the Anglo-Saxons. In the Welsh elegiac poem Gododdin, composed ca. 600, a hero is said to have fed ravens with the corpses of his enemies, "though he was not Arthur," indicating that the poet knew of an even greater hero by that name. According to a Latin History of the Britons around the year 800, ascribed to Nennius, "Arthur fought against the Saxons in those days together with the kings of Britain, but he was himself the leader of battles." Nennius names twelve such battles, in one of which Arthur is said to have carried an image of the Virgin Mary on his shoulders. The Latin Annals of Wales (ca. 950) has an entry for the year 516 concerning "the Battle of Badon, in which Arthur carried the Cross of our Lord Jesus Christ on his shoulders for three days and three nights, and the Britons were victorious."

Not until the twelfth century, though, did Arthur achieve a quasi-historical existence as the greatest of British kings in the works of Geoffrey of Monmouth, Wace, and Layamon (NAEL 8, 1.118-28). At the same time, Arthur was flourishing in Welsh tales as a fairy-tale king, attended by courtiers named Kei (Kay), Bedwyn (Bedivere), and Gwalchmain (Gawain). It was in the French literature of the twelfth and thirteenth centuries that Arthur and his knights came to embody the rise, and eventual decline, of a court exemplifying an aristocratic ideal of chivalry. In the verse romances of Chrétien de Troyes, the focus shifts from the "history" of Arthur to the deeds of his knights who ride out from his court on fabulous adventures and exemplify the chivalric ethos. Chrétien's works were adapted and imitated by writers in German, English, Dutch, and Icelandic. The new genre of romance focused not only on the exploits of knights fighting in wars and tournaments or battling against monstrous foes but also on the trials and fortunes of love, and romances addressed mixed audiences of men and women.

In the thirteenth century, a group of French writers produced what modern scholars refer to as the Vulgate Cycle, in prose. This consists of a huge network of interlocking tales, featuring hundreds of characters. The Vulgate Cycle presents a darker side to Arthur and to the Round Table as a center of courtesy and culture.

In the chronicle histories, as a Christian king, Arthur had borne the cross and fought valiantly against barbarian enemies and an evil giant. In romance, both Arthur's role and his character undergo changes inconsistent with his reputation as one of the worthies. His court continues to be the center from which the adventures of his knights radiate, but Arthur himself becomes something of a figurehead, someone whom French scholars refer to as a roi fainéant — a do-nothing king — who appears weak and is ruled and sometimes bailed out by one of his knights, especially by his nephew Sir Gawain. The very idea of Arthurian chivalry as a secular ideal undergoes a critique, especially in the Vulgate Cycle. While for the aristocracy Arthur's reign continued to provide an ancient model of courtesy, justice, and prowess, as it does in Deschamps's ballade on the Nine Worthies, moralists and satirists pointed out, with varying degrees of subtlety, how far Arthur and his knights fall short of the highest spiritual ideals. Sir Lancelot's adultery with Arthur's queen became an especially troubling factor.

In French romance, along with his uncle's, Sir Gawain's chivalry becomes equivocal and, in many respects, more interesting. In Chrétien's Yvain, Gawain serves as the advocate for male bonding, who succeeds in wooing the hero of the romance away from his newly wedded wife. In courtly romances at least (there is an exception in popular romance), Gawain never acquires a wife or even a permanent mistress like Lancelot, although there are covert and, occasionally, overt affairs with different ladies. In one late tale, Gawain agrees to woo a cruel lady on behalf of another knight, who then discovers Gawain in bed with that lady. The poet of Sir Gawain and the Green Knight may well be referring to such episodes when in the first of the three titillating bedroom scenes, he has the lady of the castle reproach Gawain for his lack of courtesy:

"So good a knight as Gawain is given out to be,
And the model of fair demeanor and manners pure,
Had he lain so long at a lady's side,
Would have claimed a kiss, by his courtesy,
Through some touch or trick of phrase at some tale's end."
      (NAEL 8, 1.189, lines 1297–1301)

French romance can help one appreciate the subtlety and delicacy of the humor with which the Gawain poet and Chaucer treat bedroom scenes. The Gauvain of French romances, however, contrasts with his English counterpart. In English romance before Malory, Sir Gawain remains Arthur's chief knight. Chaucer's Squire's Tale praises the speech and behavior of a strange knight by saying that "Gawain, with his olde curteisye, / Though he were come again out of fairye, / Ne coude him nat amende with a word." In Arthur's nightmarish dream in Layamon's Brut, Gawain sits astride the roof of the hall in front of the king, holding his sword (NAEL 8, 1.125, lines 13985–87). The English Gawain does get married in The Wedding of Sir Gawain and Dame Ragnelle, which is one of eleven popular Gawain romances surviving in English in all of which Sir Gawain is the best of Arthur's knights. That story is of special interest because it has the same plot as The Wife of Bath's Tale, except that in this tale the hero is not getting himself but King Arthur off the hook.

The legendary king of the Celtic Britons and his nephew were eventually adopted as national heroes by the English, against whose ancestors Arthur and Gawain had fought, and that is how they are presented by William Caxton in the Preface to his edition of Malory's Morte Darthur in 1485, the same year in which Henry Tudor, who thanks to his Welsh ancestry made political capital of King Arthur, became Henry VII of England. Caxton valiantly, and perhaps somewhat disingenuously, seeks to refute the notion, "that there was no such Arthur and that all such books as been made of him been but feigned and fables." Yet even after Arthur's historicity had been discredited, his legend continued to fuel English nationalism and the imagination of epic poets. Spenser made Prince Arthur the destined but never-to-be consort of Gloriana, the Faerie Queene (NAEL 8, 1.808-12, Canto 9.1–153); the young Milton had contemplated Arthur as a possible epic subject (NAEL 8, 1.1813, note 2).

The following chronology provides a selected overview of historical events and Arthurian texts: