Pembroke castle, the castle with the large tower in the film, was inherited by Richard the second following the death, in a jousting accident, of its owner John Hastings in 1389. Pembroke castle was the birthplace of the real King Henry 7th in 1457.
The trivia item below may give away important plot points.
The image of a young man full of arrows which Richard II watches being painted is a depiction of St. Sebastian, a Christian martyr killed after abandoning his military post; Richard's own murder after abandoning his crown, wherein he is riddled with arrows himself, will recall this motif. The image of St. Sebastian has become an icon of homosexuality (see Derek Jarman's film "Sebastiane"), and Ben Whishaw, who plays Richard, also played the homosexual *Sebastian* Flyte in the 2008 adaptation of "Brideshead Revisited".