Later, he continued studies at the university in Cologne, including lessons in composition with Busoni's disciple Philipp Jarnach.
In 1955, at the invitation of Erich Kleiber[1] Stein conducted at the opening of the restored Berlin State Opera (Unter den Linden),[2] and subsequently worked there as a Staatskapellmeister.
From 1961 to 1963, he worked under the leadership of Rolf Liebermann as deputy chief conductor at the Hamburg State Opera.
In 1952, Stein began work as a conducting assistant at the Bayreuth Festival to such conductors as Joseph Keilberth, Hans Knappertsbusch, Clemens Krauss and Herbert von Karajan.
One source estimates that he subsequently conducted 76 performances there from 1969 to 1986, including the 1983 Bayreuth centenary production of Die Meistersinger von Nürnberg,[4] but this figure is clearly mistaken since Stein had already led 81 in his first seven seasons.