Uncover the rich tapestry of medieval Derry, a sacred city, frontier citadel, and royal capital. This meticulously researched history explores the medieval diocese of Derry, offering a compelling narrative of saints, sinners, churchmen, and warlords. Ciaran J. Devlin's work, now with enhanced indexes by Nollaig O Muraile, provides unparalleled access to the Gaelic past of northwest Ireland. Delve into the lives of influential figures like Colm Cille, Bebhinn, and the O'Dochartaigh clan, and understand the complex interplay of religious and political power. Explore the unique social structures, monastic traditions, and key events that shaped Derry's identity. This edition, with its comprehensive indexes, is an essential resource for scholars and anyone seeking a deeper understanding of Ireland's medieval heritage.