Siege Of The Saxons (1963, U.S.A./U.K.)

Edmund of Cornwall plots to King Arthur with the help of the Saxon invaders.  However his daughter Katherine escapes with the help of outlaw Robert Marshall. Claiming she is dead, Edmund plans to usurp the throne in league with Saxon invaders. Katherine and Robert need to find wise man Merlin to help them save Camelot and England.  He orders that the  Knight wishing to marry the princess must remove the sword from the scabbard and prove his right to the throne.