Complex sentence: This work, premiered in 1905 in the same concert as Schoenberg's "Pelleas und Melisande", was considered' lost'until 1984, since when it has become one of Zemlinsky's most frequently performed scores.
Split into simpler sentences: This work, premiered in 1905 in the same concert as Schoenberg's "Pelleas und Melisande", was considered' lost'until 1984. It has become one of Zemlinsky's most frequently performed scores.