This dissertation will look at the development of the Church in the British Isles from the fifth to seventh Centuries, through the case study of Monasticism. Monasticism is a good case study as not only are there primary source documents, something rare for this period. But, monasticism also involves a social/ cultural aspect of history. In some cases the history of the Church can be insular, but the case study of monasticism introduces a breadth of historiography otherwise not available. One of the main threads in the historiography concerns itself with the structure of both the Roman and Celtic Churches. This dissertation will look at the structures of the Roman and Celtic Churches up until the Synod of Whitby in 664. The Synod of Whitby was said to have taken place to help forge unity between the two separate Churches particularly over the question of Easter, the Sacrament of Baptism, and the style of tonsure. The dissertation will look at the first missions to England and Ireland, and examine whether a lack of Roman occupation in Ireland changes the structure of the Irish Church compared to the English/Roman model. This dissertation will then go on to explain whether the Synod of Whitby’s sole goal was to solve ecclesiastical issues to mend the bridge between the two Churches, or whether the Synod was called under the pretences of more political motives.