Edited by John Thomas Gilbert (1829–98), this register was originally published in 1889 and derives from the oldest administrative manuscript that survives from Anglo-Norman Ireland. An influential historian whose work in the study of the history of Ireland had enduring impact, Gilbert notably campaigned for archival professionalism in the treatment of Irish historical documents. He was knighted in 1897. St Thomas's Abbey, Dublin, a royal foundation of Henry II, played an important role in the early Anglo-Norman settlement of Ireland. The majority of documents in its register are grants of churches and land relating to the abbey in the thirteenth century. Other notable documents highlighted by Gilbert in his preface include those relating to important figures in the abbey's history. This publication contains the Latin text of the register with English side-notes and extensive footnotes throughout, along with a helpful summary of contents.