The original first name of my grandfather, Steve Krotoczynski, who was born in Kleczew Poland, was Czapse, which appears to be a variant of Shapsei.  When he emigrated to America and then to England, he assumed "Steve" as his first name.  Later he lived in Berlin, Germany and used the German equivalent of Steve, "Stephan." I don't know about the connection between "Czapse" given at birth and his later assumed names. 

Peter Wiesner, Newtown, PA USA