Egyptian-born Roman philosopher Plotinus and his successors in the 3rd century at Alexandria founded and developed Neoplatonism, a philosophical system, which, based on Platonism with elements of mysticism and some Judaic and Christian concepts, posits a single source from which all existence emanates and with which one mystically can unite an individual soul; The Enneads collects his writings. Saint Thomas Aquinas combined elements of this system and other philosophy within a context of Christian thought. People widely consider this major of the ancient world alongside Ammonius Saccas, his teacher. He influenced in late antiquity. Much of our biographical information about Plotinus comes from preface of Porphyry to his edition. His metaphysical writings inspired centuries of pagan, Islamic, and Gnostic metaphysicians and mystics. https://en.wikipedia.org/wiki/Plotinus