How many movies have Joe May and Wilhelm Diegelmann collaborated on?

They have worked on 7 movies together! Their first movie together was The Rolling Hotel (1918) while their highest rated movie together was The Indian Tomb, Part I: The Mission of the Yoghi (1921). They have not worked together since The Indian Tomb, Part I: The Mission of the Yoghi (1921). They are most known for their drama films together.