Who Was King Arthur's Sir Modred?

Sir Modred was nephew to the King Arthur of legend; Medrawd was loyal comrade to the Arthur of history. In legend, Modred is a traitor and rebel who kills his uncle. In history, Medrawd was a warrior who fell (with Arthur) in 537 CE at "Camlan" (identified as the fort of Castlesteads, near Carlisle, northern England). Welsh bards long remembered Medrawd as a hero; Spanish readers have known Modred as a traitor since the Middle Ages. So this paper has three purposes. First, to reveal Medrawd as a historical character, a sixth-century hero of North Britain, like Arthur himself. Second, to show how Medrawd's reputation was permanently blackened in the twelfth century by Geoffrey of Monmouth. Third, to provide an etymology for Medrawd, a British form unrelated to the Cornish 'Modred' clamped upon the warrior by Geoffrey, with his usual cavalier attitude to history.