The Irish claim that their method of calculating Easter came to them via St Columba from the Apostle John himself carried great weight.

But the proponents of the Roman practice of dating Easter hit back. They first pointed out that the Irish method of calculation was confined to Ireland (and even there some of the southern churches had switched to the Roman method) and the Church of the Britons whereas the Roman method had become universal.

But the card that carried the argument for Rome was their assertion, that the Irish could not deny, that Peter had been given the keys to the kingdom of heaven and, as Rome’s chief apostle, his word carried the greatest weight.

 Given the sins that lay heavily upon Oswiu’s soul, this was a key consideration for him.