Mercia and Northumbria, therefore, owed their conversion to the disciples of Columba, and looked to the monastery of Iona as the source of their Christianity, while Kent and Wessex looked to Rome, from whence had come Augustine and Birinus. Unhappily there arose dissension between the clergy of the two churches, for the converts of the Irish monks thought that the South English paid too much deference to Rome, and differed from them on many small points of practice, such as the proper day for keeping Easter, and the way in which priests should cut their hair. King Oswiu was grievously vexed at these quarrels, and held a council at Whitby, or Streonshalch as it was then called, to hear both sides state their case before him. He made his decision in favour of the Roman observance, and many of the Irish clergy withdrew in consequence from his kingdom, rather than conform to the ways of their Roman brethren. This submission of the English to the Papal see was destined to lead to many evils in later generations, but at the time it was far the better alternative. If they had decided to adhere to the Irish connection, they would have stood aside from the rest of Western Christendom, and sundered themselves from the fellowship of Christian nations, and the civilizing influences of which Rome was then the centre (664). [Sidenote: =Archbishop Theodore.--Unification of the Church in Britain.=] The English Church, being thus united in communion with Rome, received as Archbishop of Canterbury a Greek monk named Theodore of Tarsus, whom Pope Vitalian recommended to them. It was this Theodore who first organized the Church of England into a united whole; down to his day the missionaries who worked in the different kingdoms had nothing to do with each other. But now all England was divided into bishoprics, which all paid obedience to the metropolitan see of Canterbury; and in each bishopric the countryside was furnished with clergy to work under the bishop. Some have said that Theodore cut up England into parishes, each served by a resident priest, but things had not advanced quite so far by his day. Under Theodore and his successors the bishops and clergy of all the kingdoms frequently met in councils and synods, so that England was united into a spiritual whole long before she gained political unity. It was first in these church meetings that Mercian, West Saxon, and Northumbrian learnt to meet as friends and equals, to work for the common good of them all. [Sidenote: =Prosperity of the Church.--Winfrith.--Baeda-Alcuin.=]