council · 664 · Whitby
At Streanæshalch — Whitby — in 664, king Oswiu heard Colmán for the Irish use and Wilfrid for the Roman, and chose Peter's keys. Bede tells it as the moment the English church, born of both missions, took the Roman reckoning; Lindisfarne's monks withdrew to Iona rather than conform.
The Synod of Whitby was a Christian administrative gathering held in Northumbria in 664, wherein King Oswiu ruled that his kingdom would calculate Easter and observe the monastic tonsure according to the customs of Rome rather than the customs practised by Irish monks at Iona and its satellite institutions. The synod was summoned at Hilda's double monastery of Streonshalh (Streanæshalch), later called Whitby Abbey, in modern day Yorkshire.
Northumbria torn between the Irish and Roman reckonings of Easter.
King Oswiu chose the Roman Easter and tonsure — 'lest when I come to the gates of heaven, the keeper of the keys be against me'; England aligned with Rome.