Abstract

Based on new findings about the emergence and transmission of Aristotle’s corpus in late antiquity, the paper tackles a most controversial issue : the relation of Father and Son in Symbols of Nicaea (325) and of Constantinople (381) from the strict point of view of the Greek word and concept οὐσία. The concept is shown to evolve in a few decades from individual οὐσία (e.g., Socrates and Callias), as in the Categories, to οὐσία as immaterial substance as in Metaphysics Lambda. First parchment copies of Aristotle’s Metaphysics and of the corpus, probably kept in Constantinople since about 352 AD, played a possible role.