Was Ihr wollt (1963)

Lookalike twins Viola and Sebastian are separated by a shipwreck. Viola lands in Illyria, where she disguises herself as her brother and goes into the service of the Duke Orsino, who sends her to help him woo the Lady Olivia, who doesn't want the Duke, but finds that she likes the Duke's new messenger. Then, of course, Viola's brother shows up and merry hell breaks loose. Meanwhile, Olivia's uncle and his cohorts are trying to find some way to get back at Olivia's officious majordomo, Malvolio.