By the 1890s Zemlinsky had already acquired a reputation as a promising young composer and pianist. In October 1897 Gustav Mahler had become director of the Vienna Hofoper and was determined to do what he could to help Zemlinsky. With characteristic energy Mahler worked his way through the opera with Zemlinsky, advising on and making changes in the music and the libretto. The resulting score provides a fascinating and little-explored document for both Zemlinsky and Mahler studies. Es war einmal received its first performance under Mahler on the 22 January 1900. For the Zemlinsky 150th Birthday Anniversary, Capriccio presents a new remastered edition of this legendary first recording from 1987.