The structures and concepts of ecclesiastical authority that existed in the Middle Ages fundamentally underpinned the medieval world, yet disciplinary boundaries have often inhibited scholars' approaches in this area of research. The purpose of this book is to reconsider the traditional approach to medieval Church authority, which is focused on the Church as an institution, by examining recent research in other related disciplines, such as the history of art, cultural history, liturgy, and musicology. Although work on medieval ecclesiastical authority has been undertaken separately in these different disciplines, they have not spoken to each other often enough: the studies here explicitly set out to break down these disciplinary barriers and to forge new ground in the study of a traditional subject by providing an outlet for the new research initiatives of both established and early career scholars. Power Manifest considers the topic of ecclesiastical authority in the Middle Ages, c.1100-c.1500, from a variety of disciplinary perspectives. The volume encompasses the nature of papal authority, episcopal power and the ranking of bishops at the royal court, the use of art to propound authority in absentia, the relations of the western Church with the eastern churches, the expression of ecclesiastical authority through music, the importance of collective clerical petitions, the cultural history of the papal chapel, as well as secular culture and the Church. Each contributor asks how ecclesiastical authority was conceptualised, analyses the structures through which it was expressed - in other words, how authority manifested itself as power - and most importantly, offers improved insight into the varying importance of structures and concepts under consideration. The essays all address new areas of research, and this, combined with the inter-disciplinary approaches arrayed in the volume, make it a volume which will have a significant impact on the historiography.