Sir Lancelot on horseback, by Howard Pyle, from The Lady of Shalott book by Alfred Tennyson
No list of disgraced knights would be complete without this one. Sure, Sir Lancelot may not have ever existed — and may arguably be a fiction of French lore more so than of legends across the Channel — but few falls from grace are greater than his. According to most traditions of the Lancelot “romance,” he was the peerless, shimmering warrior in King Arthur’s court, the preeminent Knight of the Round Table. But his affair with Arthur’s wife, Queen Guinevere, is the toxic force that unravels what many generations of schoolchildren imagined was the most noble, righteous Order of them all — triggering a series of treacheries and defeats that lead to Arthur’s death and the demise of Camelot.