As the cult of saints became increasingly important to the Christian religion during the latter centuries of the Roman Empire, so too the veneration of relics became a central element of Christian piety. The relics of holy men and women—the very tangibility of which ensured their lasting appeal—could be used to heal the sick, improve the weather, ensure victory in battle, and represent power and authority. Even today, in an era of declining church attendance, famous relics such as the head of St Catherine of Siena or the tongue of St Anthony of Padua continue to draw hundreds of thousands of pilgrims; the need to preserve and venerate objects associated with the important and the famous is a well-established human trait. This book is the first to explore the historical roots of the cult of relics in early medieval Ireland, deepening our understanding of how the pagan Irish adapted to the new religion. Examining the cult of relics from the earliest Irish sources up to the ninth century, it provides insights into the role of relics and the culture and people to whom they were so significant. The volume investigates how the Christian phenomenon of relic veneration developed in early Ireland and it evaluates the continuity between Irish practice and that on the continent. By offering a new model of how the cult of relics evolved and by exploring the extent to which it helped forge early Irish Christianity, the arguments presented here have the potential to reshape views of the entire period.