In this article I intend to highlight a fundamental difference that I have seized between Dionysius interpreted by Thomas of Aquinas and the author of Corpus Areopagiticum. In the first stage, I will present the way in which Thomas understands Dionysius as a simple Aristotelian, then the confession of faith of saint Thomas regarding that particular Dionysius from The Acts of Apostles 17, 34, without, however, noticing the fact that Dionysius invokes the Holy Trinity in his texts, a dogma established (...) only in the first Ecumenical Council of Nicaea . However, the most obvious issue that radically separates the two thinkers is their way of understanding theology. (shrink)