How did the Holy Roman Empire (sacrum imperium) become Holy? In this innovative book, Vedran Sulovsky explores the reign of Frederick Barbarossa (1152–1190), offering a new analysis of the key documents, artworks, and contemporary scholarship used to celebrate and commemorate the imperial regime, especially in the imperial coronation site and Charlemagne's mausoleum, the Marienkirche in Aachen. By dismantling the Kulturkampf-inspired view of the history of the Holy Roman Empire – which was supposedly desacralised in the Investiture Controversy, and then resacralised by Barbarossa and the Reichskanzler Rainald of Dassel – Sulovsky, using new evidence, reveals the personal relations between various courtiers which led to the rise of the new, holy name of the Empire. Annals, chronicles, charters, forgeries, letters, liturgical texts and objects, relics, insignia, seals, architecture and rituals have all been exploited by Sulovsky to piece together a mosaic that shows the true roots of sacrum imperium. ‘Sulovsky has produced a work that is breathtaking in its range, its erudition and the reimagining of this important moment in the history of the Holy Roman Empire. Its significance in the understanding of modern German historiography is another rich element in this study. The connection between visual culture and historical interpretation is another highlight of this work. This book is stimulating, thought-provoking, and should be read by anyone interested in this period in German history.’ Judith Collard, Parergon An in-depth exploration of Frederick Barbarossa and the origins of the term 'Holy Roman Empire'. Vedran Sulovsky is the first Saunders Research Fellow in History at Gonville and Caius College, University of Cambridge, and the recipient of the Göppinger Stauferpreis for 2023. This is his first book.