The so-called Liber diurnus Romanorum pontificum contained in the Collectio Canonum and in the Libellus contra invasores et symoniacos et reliquos scismaticos by Cardinal Deusdedit (d. 1098/1099 CE) is the oldest collection of formulae of papal documents and one of “the most contested sources of the early Middle Ages” (Kortüm, 1942). The controversies center on the date and time of its origin, its structural composition, its character, and the collection’s …