Der vertauschte Prinz (1963)

Once upon a time there was a Greek king, Kratos, who was very strict and kind-hearted. His gentle wife Arete, however, was loved by all the people. One day, the king was persuaded by his devious advisor to re-enact an ancient law, according to which the first child of the royal couple had to be a boy. When Arete gave birth to a girl, she was in great need. In order to present the king with an heir to the throne, she agreed to swap her daughter with the gardener's son...