Complex sentence: Bach's first cantata cycle refers to the church cantatas Johann Sebastian Bach composed for the somewhat less than 60 occasions of the liturgical year of his first year as in Leipzig which required concerted music.
Split into simpler sentences: Bach's first cantata cycle refers to the church cantatas Johann Sebastian Bach composed for occasions of the liturgical year of his first year as in Leipzig. There were the somewhat less than 60 occasions which required concerted music.