Complex sentence: He won the club's seventh championship title in the 2010--11 season, while in his fourth season, Dortmund won the Bundesliga and the DFB-Pokal to complete the first league and cup double in the club's history.
Split into simpler sentences: He won the club's seventh championship title in 2010--11. In his fourth season, Dortmund won the Bundesliga and the DFB-Pokal to complete the first league and cup double in the club's history.