In insisting in the preface to his work that all the domains of knowledge are useful for architecture, Vitruvius grants a dignity to all forms of learning and provides a universal entry into his work. 1 It is precisely in this affirmation that the principle of Roman encyclopaedism resides: in presenting learned factual information, it is truly destined for a readership comprised of those who are curious and desire to acquire information about a precise domain of knowledge. Clearly this must be the reason why Pliny and other Roman encyclopaedic authors very infrequently subjected different levels of transmitted knowledge to a hierarchical ranking. In effect, such a distinction does not correlate with the primary preoccupation of these authors, who prefer to