The history of monasticism in early Ireland is dominated by its flourishing during the sixth and seventh centuries, a period dominated by Columba of Iona and Columbanus of Bobbio, and later by the ’ reform’ spearheaded by Malachy of Armagh during the twelfth century. But what of monasticism in Ireland during the intervening period? Regarded as different from ’ mainstream’ Anglo-Saxon and continental monasticism, monastic life in Ireland has not been fully understood in scholarly discussions about the existence of distinct ’ monasticisms’ throughout Christianity. The Irish sources, many written in the vernacular, are not accessible and are viewed as unconventional. The secularization of monasticism in Ireland has overshadowed evidence for a thriving lived monasticism. This major study concentrates on those men and women who followed a monastic life, especially between the tenth and thirteenth centuries, and who maintained a universal monastic ideology while incorporating monasticism into their own cultural environment.