Following Finian's death, Colman became Bishop of Lindisfarne. Up to this point the Northumbrian (and latterly Mercian) churches had looked to Lindisfarne as the mother church. There were significant liturgical and theological differences with the fledgling Roman party based at Canterbury. According to Stenton: "There is no trace of any intercourse between these bishops Mercians and the see of Canterbury". The Synod of Whitby in 663 changed this, as allegiance switched southwards to Canterbury and then to Rome. Colman departed his see for Iona, and Lindisfarne no longer held its previous importance.