This book studies one of the most remarkable collections of medieval manuscripts in Ireland. In the popular mind, the medieval manuscripts of Ireland were all destroyed in the Four Courts fire of 1922 but this is far from the truth. From the 1170s, the Augustinian cathedral priory at Christ Church in Dublin commissioned, collected and used manuscript materials in its everyday life. In the process, they created an important series of codices and deeds that remained in the cathedral and so survived the Record Office fire. This large assemblage of material from the 12th-century martyrology to the 16th-century ‘Book of Obits’ reflects the changing religious, social, cultural and intellectual concerns of the world in which they were written. Each essay analyzes a manuscript and places it in its wider context; therefore this volume makes a significant contribution to the intellectual and cultural history of medieval Ireland.