Harold Godwinson
From Tardis Wiki, the free Doctor Who reference
The Thirteenth Doctor once met a King Harold, who she described as a "big fella" who was handy with a sword, and liked a good knock-knock joke.
The Doctor once told him a joke: "what do you call a knight who always cheats on a test? Sir Glancelot.(COMIC: Mistress of Chaos)
Behind the Scene
The Doctor may be referring to Anglo-Saxon king Harold Godwinson.
