Complex sentence: Born in Munich, he studied in that city with E. Kirschner before joining the Munich Opera in 1892; there he remained for 12 years, at the same time appearing in most of the major German opera houses.
Split into simpler sentences: Born in Munich, he studied in that Bavarian city with E. Kirschner before joining the Munich Opera in 1892. He remained there initially for 12 years, at the same time appearing in most of the major German opera houses.