Iamblichus 245 AD – 325 AD

Iamblichus of Chalcis was a Syrian Greek Neoplatonist philosopher and the founder of the Syrian school of Neoplatonism. Departing from Plotinus and Porphyry, he held that intellectual contemplation alone is insufficient for the soul's ascent and that ritual practice, or theurgy, is also required to unite with the divine. He composed a Pythagorean encyclopedia, of which the Life of Pythagoras and Protrepticus survive, and his treatise On the Mysteries defended the religious philosophy that would shape the last phase of pagan thought.

Iamblichus was born around 245 AD at Chalcis in Coele Syria, into a family that the doxographic tradition connected with the priest-kings of Emesa. He studied with the Christian convert turned Neoplatonist Anatolius and, later in life, with Porphyry, before returning to Syria around 305 AD and founding his own school, probably at Apamea, that became the principal center of late Greek Platonism for the next generation.

Of his enormous output only fragments and a few works survive: the Life of Pythagoras, the Protrepticus, the treatises On the Common Mathematical Science and On Nicomachus's Arithmetical Introduction, and the famous On the Mysteries of the Egyptians (De mysteriis), a defense of theurgy against criticisms in Porphyry's Letter to Anebo. Substantial portions of his commentaries on Plato and Aristotle are quoted in later Neoplatonic authors.

Iamblichus made theurgy — ritual ascent through divinely instituted symbols — central to philosophical practice and elaborated the Plotinian metaphysics into a much more finely articulated hierarchy of divine henads, intelligible gods, and intracosmic powers. The Athenian school of Plutarch, Syrianus, and Proclus, the emperor Julian's pagan revival, and the Florentine Platonism of Marsilio Ficino all stand under his influence. He died around 325 AD.