"The documentary sources only give a limited account of Streaneshalch’s history, but the most important event, the Synod of Whitby in 664, was described in some detail by Bede. Here, the rivalry between the two strands of Christianity in England, the Celtic and the Roman, came to a head.
Christianity had been brought to Northumbria not only by missionaries from Rome but by Celtic missionaries from Iona in Scotland. The two traditions differed over such issues as how priests and monks should dress and wear their hair, and, most notably, how the date of Easter should be calculated. Eventually King Oswiu decided that the Roman side should prevail, and the Pope’s authority was gradually established over the Church in the British Isles."
*In short, this took place at Abbey of Whitby or Synod of Whitby.*