Gothic architecture was first introduced into Ireland by the 12th-century church reform movement and during the Anglo-Norman conquest in the 13th century. Little evidence survives to identify the imported workforce except for their individual signature marks which are not found before the conquest. Houritane presents a thorough study of the marks to untangle the complicated regional architecture of medieval Ireland. The marks have enabled him to place a number of important buildings within groups and thereby propose a new dating framework for the buildings. Includes a comprehensive catalogue with illustrations of the marks.