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