There is scarcely need to exaggerate the importance of Liber pontificalis, or Liber episcopalis in quo continentur acta beatorum pontificum urbis Romae (The Pontifical Book in which are gathered the activities of the blessed pontiffs of the City of Rome). The series of biographical notices that makes up Liber pontificalis was carried on from one continuator to the next until, in 1479, Bartolomeo Sacchi da Platina replaced it with a model better suited to the dawn of the modern age. 1 In this sense, Liber pontificalis is a written monument, even if not properly speaking a literary one, able both to stimulate its own perpetuation for almost a millennium and to provoke a famous imitation by Agnellus of Ravenna (around 839), otherwise extremely hostile to Roman initiatives regarding his church. 2 Its capacity to do this, a form of continual rebirth, is perplexing and calls for a consideration of the work’s original characteristics in order to discern its dynamic force. Such an investigation, initiated long ago and pursued with the characteristic rigour and insight of two of the greatest scholars, Mommsen 3 and Duchesne, 4 at the end of the nineteenth century, has been recently renewed, above all by H. Geertman. 5 It has allowed us to appreciate just how Roman the biographical genre was from which Liber pontificalis stemmed. Its subject was none other than the head of the institution that stepped into the shoes of imperial power, concentrating in the urbs the display of its religious power and establishing, with the urbs at its centre, an efficient network of command and representation. In this way, each pontifical biography is fashioned according to identifiable categories with distinct rubrics, to which we shall come back later. It is enough to note for the moment that our series of lives belongs to a long tradition which, notwithstanding significant transformations, reaches back to Suetonius. 6