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.
Lancelot is King Arthur's most valued Knight of the Round Table and a paragon of courage and virtue. Things change, however, when he falls for Guinevere (Wallace), bride of Arthur (Brian Aherne, who had essayed this character more than once, e.g. in 1954's Prince Valiant), and she for him.
Made ten years after Richard Thorpe's film Knights of the Round Table, the illicit romance this time is portrayed as a more intimate affair, and the sword fights have a more menacing reality (Wilde was an excellent fencer). A sub-plot concerns Arthur's effort to forestall a challenge from a rival king, a problem that will inevitably catch Lancelot up in a personal conflict.