Reading Gibbon's "Decline and Fall" - Chapter XXI: Heresy and paganism

We start briefly with the Donatist schism, which was basically political; and then we have a prolonged and detailed discourse on Platonism and the doctrine of the Trinity, which I must say explained both in more lucid and provocative terms than I recall reading anywhere else. Constine's inconstancy opens up further room for debate between Arius and the Catholics, led by Athanasius who gets about a third of the chapter to himself. Finally a brief survey of how well (or badly) the old beliefs were surviving.