Thus in the south the conversion of the English had been effected by the missionaries from Rome ; in the middle and north by those from Iona. The former derived their authority from the bishop of Rome, the pope; the latter from Columba, the bishop of Iona. Both were Christian churches, but they differed from each other in certain matters of ritual, such as the way of calculating Easter and the shaving of the head in the tonsure. These matters, slight as they seem, were of sufficient importance to prevent the Celtic church from cooperating with the Roman, even though as early as the days of Augustine conferences had been held on the subject.
In reality, however, there existed between the two churches differences of far greater moment than those which concerned Easter and the tonsure. The Roman missionaries were fewer in number, but more powerful because they had behind them the growing church of the Continent; the Celtic missionaries were more numerous and had made their influence felt over a greater extent of territory, but because of their isolation were less powerful. The Roman missionaries had sought to convert kings and others politically influential ; the Celtic, to convert the people; and while the former had used outward ceremony and display, the latter had preached the word of God humbly, seeking to influence by precept and example. Again, and most important of all, the representatives of the Roman church had borrowed from the imperial organization of Rome advanced ideas of the way the church should be united under one head and made subject to a single authority; whereas the Celtic representatives had no idea of organization, but had built up, separate churches in each tribe with no more unity than the tribes themselves had.. Between these two systems, the Roman with its centre at Canterbury, the Celtic with York as its most influential city, there was bound to come a conflict. This conflict was settled at the synod of Whitby.

CELTIC CROSS AT IONA.
This cross stands near the road leading from the landing place to the ruins of the cathedral.
By 664 controversies between the two churches regarding the keeping of Easter and other rules of ecclesiastical life had become so frequent that Oswiu called a synod in the monastery of Whitby. After elaborate arguments had been presented by Wilfrid for the Roman party and Colman for the Celtic, Oswiu turned to Colman and said, "Is it true that Peter has received the keys of Heaven, as Wilfrid says ?" Colman answered, It is true, 0 king." Then said Oswiu, Can you show any such power given to your Columba?" "None." Then said the king, "Peter is the doorkeeper, and him I will not contradict, lest when I come to the gates of the kingdom of Heaven there should be none to open them, he being my adversary who is proven to have the keys." Thus a momentous decision was made by the king and assented to by his councillors. The English church became henceforth a part of the great Continental church, of which the bishop of Rome was rapidly be-coining the recognized head, or pope; and it was destined to enjoy not only all the advantages that came from contact with the more advanced civilization of the Continent, but also all the benefits that a more highly organized church system could confer. The Celtic clergy, with Colman at their head, left Northumbria to continue in Strathclyde and Pictland the work of the Celtic church, which from this time forward became only of local importance. On the other hand, the Roman system, before a century had passed, was destined to become dominant in England as far north as the region about Edinburgh, and to aid greatly in furthering the national unity both of England and of Scotland.
