The Adventures of Sir Galahad (1949)
Director: Spencer Gordon Bennett
Cast: William Fawcett, Lois Hall, Nelson Leigh and George Reeves

A knight, who in order to join King Arthur and his famous table, must obtain the missing obtain the missing sword Excalibur whose powers can render a person invisible. Sir Galahad is hindered in his quest by the occupying Saxons in general and by Merlin the Magician and a mysterious Black Knight in particular.