Lancelot and Guinevere (1963)
Lancelot and Guinevere (known as Sword of Lancelot in the U.S.) is a British 1963 film starring Cornel Wilde, his real-life wife at the time, Jean Wallace, and Brian Aherne. This lesser-known version of the Camelot legend is a work almost solely made by Cornel Wilde, who co-produced, directed, co-wrote, and played Lancelot.
More at Wikipedia.