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.