Augustine of Canterbury was Prior of a church in Rome when Pope Gregory I asked him to lead a missionary quest to the Kingdom of Kent on the island of Britain. The Pope wrote letters to the Frankish kings and queens along the route, ensuring Augustine and his entourage of forty priests and monks would have a welcome journey. They arrived in Kent in 596 CE, welcomed by the Catholic Queen who had sent for them, Bertha, and her tolerant pagan husband, Æthelberht. The king gave the missionaries land to build a monastery, and welcomed them to seek converts among his people.
By 601, Æthelberht was a baptised Catholic. Gregory was pleased with Augustine and sent him a special white scarf with black crosses in 601. It was made from wool raised by sheep at a particular nunnery, reserved only for popes and those they choose to honor. The current pope wears such a stole from lambs descended from the very same herd. Augustine’s mission work was slow but steady, following Gregory’s preferred style of persuasion rather than coercion. He was a Pope who avoided bloodshed as best he could, an urban politician, not a holy crusader. Paganism continued to be practiced in Kent through the 630s and was not outlawed until 640.
While Augustine had great success with converting the Anglo-Saxon pagans, he struggled with the other aim of his mission: bringing the Celtic Christians back in line with Roman Christian doctrine. Christians had been in other parts of England – and in Ireland, Scotland, and Wales – long before Augustine arrived on Kentish shores. They just weren’t the right sort of Christians. They didn’t do baptism right, they had the wrong haircut, and they didn’t know when Easter was.
Augustine wrote that they did “incomplete” baptisms, but not exactly what that meant. They two groups argued incessantly over tonsure or the proper haircut for a monk. Roman tonsure was in a halo style, with the top and center of the head shaved, and the hair clipped fairly short. We don’t have any surviving paintings to be certain of the Celtic tonsure style, but the general consensus was shorn from one ear to the other, over the dome of the head, and otherwise uncut. A tonsure mullet if you will: holy in the front, party in the back. This was a major point of contention between Augustine and the Celts.
The other was the timing of Easter, and the related timing of Passover. Since the beginning of Christianity this has continued to be a sticking point in church orthodoxy and religious continuity between groups of Christians. The Celts were accused of observing Easter on the 14th of the Jewish month Nissan, which was not true, but is important to consider. The Celtic form of “heresy” was perceived as a type of Judaizing.