Abstract
According to the Aristotelian account of substantial change, that is, the corruption of one substance and the generation of another, prime matter must be found at the starting and at the end point of change, as that which persists throughout the change. But knowing that matter remains as the substrate of change tells us little about the nature of this matter, which constitutes both the corrupted substance and the new generated substance. Among the questions we can ask about its nature are whether prime matter is an entity of its own apart from form; whether it is one in all those individual material substances or is somehow divided or partitioned into different parts. Early commentaries on the Physics and Metaphysics were interested in precisely these questions about the unity and divisibility of prime matter and about what kind of unity this may be. This article aims to investigate how authors from the English commentary tradition in the period 1250–1270 answered these questions.