The inhabitants of early medieval Britain and Ireland shared the knowledge that the region held four peoples and the awareness that they must have originally come from ‘elsewhere’. The Origin Legends of Early Medieval Britain and Ireland studies these peoples’ origin stories, an important genre that has shaped national identity and collective history from the early medieval period to the present day. These multilingual texts share many common features that repay their study as a genre, but have previously been isolated as four disparate traditions and used to argue for the long roots of current nationalisms. Yet they were not written or read in isolation during the medieval period. Individual narratives were in constant development, written and rewritten to respond to other texts. This book argues that insular origin legends developed together to flesh out the history of the insular region as a whole.