Complex sentence: He became assistant to Rudolf Höß, the Commandant at Auschwitz in 1940 and later was named Commandant of Natzweiler-Struthof concentration camp in April 1941.
Split into simpler sentences: He became assistant to Rudolf Höß, the Commandant at Auschwitz in 1940. Kramer named Commandant of Natzweiler-Struthof concentration camp in April 1941.