How many movies have Erwin Fichtner and Willy Zeyn Sr. collaborated on?

They have worked on 2 movies together! Their first movie together was Der Hund von Baskerville - 5 Teil: Dr. Macdonalds Sanatorium (1920) and was their highest rated movie together. They have not worked together since Der Hund von Baskerville - 6. Teil: Das Haus ohne Fenster (1920).