Simplify the following text for a Grade 7 native English-speaking person.
Original: Per Wiberg also joined the band on tour to perform keyboards , and after more than a year on tour , Opeth returned home to start writing new material in 2004 .
Simplified: Per Wiberg also joined the band on keyboards , and after more than a year on tour , Opeth went back home to start writing more new songs in 2004 .