Lancelot
From Tardis Wiki, the free Doctor Who reference
Sir Lancelot was a knight in the service of King Arthur. He was the subject of several works of fiction. The Second Doctor summoned Sir Lancelot in his mental battle with the Master of the Land. (DW: The Mind Robber)
The Fourth Doctor claimed to have taught Lancelot how to use a sword. (PDA: Wolfsbane)