Complex sentence: Returning to Düsseldorf in 1919, he was a founder of the "Junge Rheinland" (Young Rhineland) group, and in 1921 he married the journalist Hulda Droste.
Split into simpler sentences: Returning to Düsseldorf in 1919, he was a founder of the "Junge Rheinland" (Young Rhineland) group. In 1921 he married the journalist Hulda Droste.