The Pagan Book Inside Christian Mysticism

The Elements of Theology is Proclus at his most austere: two hundred and eleven propositions, each proved from the ones before, a geometry of the divine written by the last great head of the Athenian school. Its afterlife is one of the strangest transmission stories in the history of ideas, because the most influential readers of this militantly pagan book were Christians and Muslims who did not know they were reading it. Around the turn of the sixth century an unknown Christian writing as Dionysius the Areopagite, Paul's Athenian convert, rebuilt Proclus's hierarchies into the celestial and ecclesiastical hierarchies of Christian mysticism; the apostolic name carried the system into the heart of the church, which took from it much of its angelology and its negative theology alike.

Separately, an Arabic compiler distilled the Elements into a short work that reached Latin readers as the Liber de Causis and circulated for a century as Aristotle's own theology. Aquinas, comparing it against William of Moerbeke's fresh translation of Proclus in 1268, recognised the true source and said so. Proclus himself, hymn writer, commentator on Euclid and the Timaeus, and practitioner of the theurgy he defended, was on the losing side of history in his lifetime: the school he served was closed by Justinian in 529, and his system survived best inside the religion that closed it.