Who composed in Charlemagne's name the impressive treatise that repudiates the Acts of the Second Council of Nicaea (but which, in the end, the king prevented for religio-political reasons from circulating in his own day)? This series of essays explores in turn the liturgical background, the Latinity, attitudes towards images and the historical circumstances of the time, including relations between Charlemagne, the pope and Byzantium. Ann Freeman presents solid evidence for identifying Charlemagne's spokesman as Theodulf, a Visigoth and refugee from the Moorish invasions of Spain, and reveals the impressive extent of the learning he brought with him - which lead eventually to his appointment as Bishop of Orléans. The final and most up-to-date summary of the findings concerning Theodulf's authorship was presented in German in the introduction to her new edition of the Opus Caroli regis contra synodum (formerly known as the Libri Carolini); the original English version of this is now published here.