Premise: Impossible Love (German:Unmögliche Liebe) is a 1932 German drama film directed by Erich Waschneck and starring Asta Nielsen, Ery Bos and Ellen Schwanneke. It was the final film of Nielsen, and the only sound film she appeared in. It is also known by the alternative title of Crown of Thorns.
Hypothesis: Waschneck directed multiple sound films starring Nielsen