King Arthur - Historicity
Any discussion of the Arthurian mythos must begin with Arthur himself - specifically, whether he existed at all. The answer is an unsatisfying "probably".
The problem is the abysmal lack of historical evidence concerning the period between the end of the Roman rule over Britain (early fifth century) and the end of the Saxon conquest of Britain (late sixth century). There are virtually no surviving written records from Britain during this 150-year period. What we do know of this dark age, often called the "Arthurian period", is constructed basically from four sources:
Existing British written sources
For our purposes, this is only a single source: Gildas' De Excidio et Conquestu Britanniae ("Of the Ruin and Conquest of Britain"), written about 540, forty to eighty years after the time of a "historical" Arthur. Unfortunately, Gildas was writing a diatribe, not a history, and he never mentioned Arthur's name. He outlines the Roman and post-Roman era before launching a tirade against the lechery of rulers living in his own time. Gildas does not mention Ambrosius (later to become Arthur's uncle), and probably Vortigern, and other characters who become linked to Arthur in later chronicle and legend.
He tells of the great Saxon defeat at Mount Badon, but does not name the British leader. In later sources, this man is to be named as Arthur. Gildas' omission of Arthur's name is frustating, but is hardly conclusive given the intent and form of his work.
Excavations throughout Britain cast light onto living conditions, military circumstances, settlements, and so on. Unfortunately, archaeology cannot, for the most part, provide name. Still, it has contributed valuable information to the Arthurian question. To use one example, sixteenth-century writer John Leland's identification of Camelot with Cadbury is lent support by Leslie Alcock's excavations at Cadbury, which suggest that it was an important military headquarters during the late fifth century.
Histories written on the contintent during this period provide some slight information on the situation in Britain, though none of them mention Arthur specifically. Gregory of Tour's History of the Franks and Jordanes' Gothic History are two examples.
The latter provides information about Riothamus, a late fifth-century king of the Britons who some have connected to Arthur. Riothamus reportedly brought an army of Britons into Gaul, at the behest of the Romans, to deal with the Visigoths. Riothamus was defeated. Forced to retreat, he disappeared into Burgundy, near a place called Avallon.
Later British Sources
Nennius' Historia Brittonum and the Annales Cambriae are two sources written within 500 years of the Arthurian period that provide information on British history and on Arthur specifically. Nennius lists twelve great battles fought between Arthur against the Saxons, including Badon.
The Annales also tell of Arthur's victory at Badon and, later, "the strife of Camlann, in which Arthur and Medreaut (Mordred) fell..." The problem with this later sources is not only that they were written hundreds of years after the events described, but also that they have become so tainted with legend as to have their historical veracity impeached. Nennius, for instance, says that Arthur killed 960 men himself at the battle of Badon, and the Annales entry prior to Badon tells of a bishop who lived to be 350 years old.
There are three other factors that argue for the existence of an historical figure named "Arthur". The first is literary: around the year 600, a northern bard named Aneirin wrote Y Gododdin, a lamentation describing the deaths of British warriors against the Angles at the battle of Catraeth. In one stanza, a warrior's prowess is extolled; however, the warrior "was not Arthur", meaning that his skill in battle was second only to a mighty (and presumably famous) warrior named Arthur. Clearly, the audience of the poem was expected to know the identity of "Arthur"; conventional scholarship holds that the reference alludes to the famed battle-leader of a century prior, but some scholars have argued that the passage refers to Arthur of Dalriada, a northern figure who lived contemporary to the writing of Y Gododdin, and in close geographic proximity to its writer and audience.
It is clear, too, that a great body of Arthurian oral tradition developed among the Celts between the sixth and twelfth centuries. There are allusions to tales in this tradition in the Welsh Triads, the Black Book of Carmarthen, the body of literature called the Mabinogion, and other sources. Most of these were written late, but they bespeak a much earlier tradition. It is almost inconceivable that some historical figure named Arthur did not exist to inspire an oral tradition of such heroic proportions.
Finally, Arthurian scholars note the increased usage of the name "Arthur" in the two centuries following the "Arthurian period". Irish princes are recorded with the name in the sixth and seventh century, as a Welsh prince who ruled Dyfed in the early seventh century, a British prince who lived in the seventh century, and another Irishman. Logic dictates that some noteworthy historical figure named "Arthur" existed to inspire the subsequent uses of the name.
This can be considered the hypothetical sum of these fragments, investigations, and allusions:
Arthur was a British war-leader who, continuing a revolt begun by Ambrosius before him, battled the Saxon invasions in the late fifth or early sixth century. He may have been a regional ruler, and may have held the title of "king", or he may have been a general under another king or collection of kings. He was almost certainly of Roman descent, with Roman ideas. He may have revived the Roman cavalry in Britain as a means to achieve victory. His headquarters may have been Cadbury.
He enjoyed several successes before he smashed the Saxons at Badon Hill, causing them to retreat to their settlements on the eastern shore. Several decades of relative peace followed, with no further Saxon encroachments. Arthur may have enjoyed further victories in Gaul. He possibly died at a battle called "Camlann", fighting someone named Medraut. On the other hand, if he is indeed indentical to Riothamus, he eventually led a military excursion into Gaul to help Rome drive away the Visigoths under Euric. He was betrayed by the Roman prefect in Gaul and defeated by the Visigoths. His death is not reported, but he is last recorded in Burgundy near a place called Avallon.
There are a lot of "ifs" in this summary, and it must be considered that "Arthur" may be multiple people (cf. Arthur of Dalriada, Riothamus), fused through legend and hazy history, into a single character.