The twelfth century saw a wide-ranging transformation of the Irish church, a regional manifestation of a wider pan-European reform movement. This book, the first to offer a full account of this change, moves away from the previous concentration on the restructuring of Irish dioceses and episcopal authority, and the introduction of Continental monastic observances, to widen the discussion. It charts changes in the religious culture experienced by the laity as well as the clergy and takes account of the particular Irish experience within the wider European context. The universal ideals that were defined with increasing clarity by Continental advocates of reform generated a series of initiatives from Irish churchmen aimed at disseminating reform ideology within clerical circles and transmitting it also to lay society, even if, as elsewhere, it often proved difficult to implement in practice. Whatever the obstacles faced by reformist clergy, their genuine concern to transform the Irish church and society cannot be doubted, and is attested in a range of hitherto unexploited sources this volume draws upon. Marie Therese Flanagan is Professor of Medieval History at the Queen's University of Belfast.