Syrianus, originally from Alexandria, moved to Athens and became the head of the Academy there after the death of Plutarch of Athens. Syrianus attacked Aristotle in his commentary on Books 13 and 14 of the "Metaphysics", just as his pupil Proclus was to do later in his commentaries on Plato. This is because in "Metaphysics 13-14", Aristotle himself was being thoroughly polemical towards Platonism, in particular against the Academic doctrine of Form-numbers and the whole concept of separable number. In reply, Syrianus gives an account of mathematical number and of geometrical entities, and of how all of these are processed in the mind, which was to influence Proclus and all subsequent Neoplatonists.