Plotinus
Greek-speaking philosopher of the Roman era (c. 204–270 AD), probably born in Egypt, trained in Alexandria under the mysterious teacher Ammonius Saccas for eleven years, and the founder — though he himself considered himself simply a faithful interpreter of Plato — of Neoplatonism, the philosophical current that would dominate the final period of ancient philosophy and exert a decisive influence on medieval Christian, Islamic and Jewish thought alike. He travelled to Persia and India with the army of Emperor Gordian III to study Eastern philosophies, eventually settling in Rome, where he taught for over twenty years in a circle that included senators and, perhaps, the Emperor Gallienus himself, who seriously considered funding a project to found an ideal philosophical city on Platonic principles, 'Platonopolis', which ultimately never materialised. He wrote nothing until the age of forty-nine; his disciple and biographer Porphyry later compiled and organised his writings into six groups of nine treatises each, hence the name Enneads ('the Nines') by which his complete work is known. The core of his system is the doctrine of the One (to Hen), an absolutely simple, transcendent and ineffable principle, beyond even being and thought, from which all reality emanates in a series of descending degrees of perfection: first the Intellect (Nous), where the Platonic Forms reside, then the Soul, and finally matter, at the opposite extreme of perfection. Philosophical life, for Plotinus, consists in a reverse process of contemplative ascent from material multiplicity to mystical union with the One, an experience he himself claimed to have attained several times during his life — a fusion of metaphysical rigour and mystical experience that profoundly marked both Christian negative theology and Islamic Sufi mysticism.