EN
The paper deals with Aquinas' concept of the individuation of material beings. The author tries to show that Aquinas throughout his whole scholarly career held the view that designated matter is the principle of individuation for corporeal beings. However, Aquinas had changed (many times) his view concerning the kind of dimensions involved in individuation, i.e. dimensions that make matter to be undivided. The author turns to a number of texts where Aquinas addresses the problem in order to show his changes of view and in order to properly elucidate Aquinas' solution.