I’ll be presenting a paper on challenges often met during the conservation of medieval monuments and places at the seventh “Space and Settlement in the Middles Ages” interdisciplinary conference in Trinity College Dublin, 20-21 May 2016. The talk focuses on the interpretation of historical and archaeological information to guide the conservation of medieval buildings. Medieval buildings have often been adopted and adapted for different uses throughout their history, and a substantial part of our medieval architectural heritage survives in a ruined condition. Conserving a structure often necessitates some form of intervention, especially where the monument is ruined. The conservation of ruins is an illogical practice in some respects, and at odds with what most professionals are trained to do – to mend damaged buildings and make them useful again. Yet many medieval sites are preserved and maintained as ruins, and visited by a growing number of people who see values, significance and meaning in medieval buildings despite their condition. This talk considers the assessment of available historical and archaeological evidence and its usefulness where conservation decisions are complicated due to the significant but very different types of change to an original building configuration over time.