Complex sentence: Rheinhold was protective of his Jewish heritage being a strong influence in the Deutsch-Israelitischer Gemeindebund (an association of Jewish corporations) and sculpting "Die Kämpfer" ("The Warriors") in protest against burgeoning anti-Semitism.
Split into simpler sentences: Rheinhold was protective of his Jewish heritage, and was a strong influence in the Deutsch-Israelitischer Gemeindebund (an association of Jewish corporations). He sculpted "Die Kämpfer" ("The Warriors") in protest against burgeoning anti-Semitism.