Fiddlers Three (1948)

The stooges are musicians at the court of King Cole. When they ask the king's permission to marry their sweethearts, the King agrees, but only after Princess Alicia has married Prince Valiant. This news upsets Mergatroyd, an evil magician who plans to marry the Princess himself and rule the Kingdom. Mergatroyd abducts the Princess, and it's up to the stooges to foil his plans and expose his evil doings.