Complex sentence: The Symphony No.70 in D major (Hoboken 1/70) was written by Joseph Haydn in 1779 to mark the start of construction of a new opera house on the Eszterháza estate.
Split into simpler sentences: The Symphony No.70 in D major (Hoboken 1/70) was written by Joseph Haydn. It was written in 1779 to mark the start of construction of a new opera house on the Eszterháza estate.