Complex sentence: The Symphony No.14 (Opus 135) by Dmitri Shostakovich was completed in the spring of 1969, and first performed in Leningrad on 29 September 1969 by the Moscow Chamber Orchestra under Rudolf Barshai.
Split into simpler sentences: The Symphony No.14 (Opus 135) by Dmitri Shostakovich was completed in the spring of 1969, and was premiered later that year. The work received its official premiere in Leningrad on 29 September 1969 by the Moscow Chamber Orchestra under Rudolf Barshai.