Complex sentence: It was their first full season under French manager Arsène Wenger, who became the third non-English manager to win the Premiership after Alex Ferguson and Kenny Dalglish, and the first manager from outside the British Isles ever to win the league title in England.
Split into simpler sentences: It was their first full season under French manager Arsène Wenger, who followed in the footsteps of Alex Ferguson and Kenny Dalglish. While both Ferguson and Dalglish were Scottish, Wenger was the first manager from outside the British Isles to win the league title in England.