The ecclesiastical Act Book for the southern part of the diocese of Armagh covering the years 1518–1522 is a unique survival for Ireland. Covering the marital, sexual, testamentary, reputational and other squabbles of men and women living in modern Co. Louth and adjoining counties it offers a rare and vivid glimpse into the lives of ordinary individuals in early sixteenth-century Ireland. The huge wealth of place and personal names preserved in just over 140 entries give important clues as to the ethnic composition of the Pale through the proceedings of a busy and popular court which sat in Drogheda, Termonfeckin and Dundalk. This volume provides an edited text of the original Latin manuscript along with an English summary of each case. Compiled just under twenty years before Henry VIII’s break with Rome, the Act Book of Archbishop Cromer is a key source for understanding the place of the pre-reformation church in Irish society.