Mordred

The oldest surviving mention of Mordred, under the Welsh form Medraut, gives almost nothing away. The Annales Cambriae, a chronicle compiled in the tenth century from earlier material, records for a year usually reckoned as 537 only that the Battle of Camlann took place, in which Arthur and Medraut fell, with no statement of whose side Medraut fought on, what caused the battle, or what relationship, if any, connected the two men. This bare entry is one of the very few pieces of evidence historians who argue for a real figure behind the Arthur legend can point to, and it is exactly this bareness that leaves the door open for every later writer to fill in the story however the developing legend needed: an ally who fell fighting beside Arthur, an enemy who killed him, a usurper, or eventually a son. Geoffrey of Monmouth, writing his Historia Regum Britanniae some six centuries after the annal entry, is the first surviving text to resolve the ambiguity decisively, casting Medraut, in his Latin the more familiar Modredus, as Arthur's own nephew and a straightforward traitor, the shape nearly every later telling of the story would keep even as it added new layers on top of it.

Geoffrey of Monmouth's account of Mordred, the earliest full literary telling, makes him Arthur's nephew, the son of Arthur's sister Anna and King Lot of Orkney, a genealogy that gives Mordred a legitimate blood claim to stand as regent while Arthur campaigns abroad and makes his usurpation a betrayal of family trust rather than an outsider's naked ambition. That nephew relationship holds through several centuries of retelling before the developing prose tradition adds a far darker layer. The Vulgate Cycle, and Malory's English Le Morte Darthur following it, introduces an episode in which Arthur, not yet aware of his own parentage or hers, sleeps with his half sister, usually named Morgause in the English tradition, and conceives Mordred in that unwitting incest, so that the nephew of Geoffrey's account becomes, in this later strand, Arthur's own son as well. Malory has Merlin warn Arthur of a prophecy that a child born on May Day will one day destroy him, prompting Arthur to send every child born that day out to sea in a doomed attempt to drown the danger before it can grow, an act of attempted infanticide the infant Mordred alone survives, so that Arthur's own effort to escape the prophecy becomes, in the story's own logic, part of what guarantees it comes true.