Complex sentence: He was engaged at the Staatstheater Braunschweig from 1962 and at the Städtische Bühnen Münster to 1965, when he moved to the Staatsoper Hannover where he performed major parts as a Heldentenor and in Italien opera.
Split into simpler sentences: He was engaged at the Staatstheater Braunschweig from 1962 and at the Städtische Bühnen Münster to 1965. He then moved to the Staatsoper Hannover where he performed major parts as a Heldentenor and in Italien opera.