Complex sentence: After her Metropolitan career Bella Alten-Deri (she married in 1912 to Hermann Deri, an Austrian State Banker) returned to Vienna and contined to sing at both the Hofope and Volksoper.
Split into simpler sentences: After her Metropolitan career Bella Alten married Hermann Deri, an Austrian State Banker, and became Bella Alten-Deri. She returned to Vienna and contined to sing at both the Hofope and Volksoper.