Between the fifth and ninth centuries AD, the peoples of Britain, Ireland, and their surrounding islands were constantly interacting-sharing cultures and ideas that shaped and reshaped their communities and the way they lived. The influence of religious figures from Ireland on the development of the Church in Britain was profound, and the fame of monasteries such as Iona, which they established, remains to this day. Yet with the exception of St Patrick, far less attention has been paid to the role of the Britons and Picts who travelled west into Ireland, despite their equally significant impact. This book aims to redress the balance by offering a detailed exploration of the evidence for British and Pictish men and women in the early medieval Irish Church, and asking what we can piece together of their lives from the often fragmentary sources. It also considers the ways in which writers of later ages viewed these migrants, and examines how the shaping of the 'migration narrative' throughout the centuries had a major effect on the way that the earliest centuries of the church came to be viewed in later years in both Scotland and Ireland. In doing so, this volume offers important new insights into our understanding of the relationships between Britain and Ireland in this period.