Plotinus (204-270 A.D.), was a major Hellenistic philosopher who lived in Roman Egypt and whose teacher was Ammonius Saccas. His philosophy, described in the Enneads, states there are three principles: the One, the Intellect, and the Soul.
His metaphysical writings have inspired centuries of Pagan, Jewish, Christian, Gnostic, and Islamic metaphysicians and mystics, including developing precepts that influence mainstream theological concepts within religions, such as his work on duality of the One in two metaphysical states.