Augustine and his monks were not, however, the only Christians in the British Isles. Britain had been converted to Christianity when it was a Roman province, and some of the missionaries, led by St. Patrick (d. about 469), had made their way into Ireland and established a center of Christianity there. When the Germans overran Britain and reheathenized it, the Irish monks and clergy were too far off to be troubled by the barbarians. They knew little of the traditions of the Roman Church and diverged from its customs in some respects. They celebrated Easter upon a different date from that observed by the Roman Church and employed a different style of tonsure. Missionaries from this Irish church were busy converting the northern regions of Britain, when the Roman monks under Augustine began their work in the southern part of the island. [Sidenote: Conflict between the Roman Church and the Irish monks.] There was sure to be trouble between the two parties. The Irish clergy, while they professed great respect for the pope and did not wish to be cut off from the rest of the Christian Church, were unwilling to abandon their peculiar usages and accept those sanctioned by Rome. Nor would they recognize as their superior the Archbishop of Canterbury, whom the pope had made the head of the British church. The pope, on his part, felt that it was all-important that these isolated Christians should become a part of the great organization of which he claimed to be the head. Neither party would make any concessions, and for two generations each went its own way, cherishing a bitter hostility toward the other. [Sidenote: Victory of Roman Church.] At last the Roman Church won the victory, as it so often did in later struggles. In 664, through the influence of the king of Northumbria who did not wish to risk being on bad terms with the pope, the Roman Catholic form of faith was solemnly recognized in an assembly at Whitby, and the leader of the Irish missionaries sadly withdrew to Ireland. [Illustration: Map of Christian Missions] The king of Northumbria, upon opening the Council of Whitby, said "that it was proper that those who served one God should observe one rule of conduct and not depart from one another in the ways of celebrating the holy mysteries, since they all hoped for the same kingdom of heaven." That a remote island of Europe should set up its traditions against the customs sanctioned by the rest of Christendom appeared to him highly unreasonable. This faith in the necessary unity of the Church is one of the secrets of its strength. England became a part of the ever-growing territory embraced in the Catholic Church and remained as faithful to the pope as any other Catholic country, down to the defection of Henry VIII in the early part of the sixteenth century. [Sidenote: Early culture in England.] [Sidenote: The Venerable Bede.]