Xenocrates was a philosopher of ancient Greece, born at Chalcedon, who governed the Academy as successor to Speusippus, himself the successor of Plato, from 339 BC till his death. He wrote numerous treatises up[on dialectics, physics, and ethics, of which the titles only have been preserved; and what is known of his doctrines is gathered only from notices in various authors. He introduced into the Academy the mystic Pythagorean doctrine of numbers in connection with the ideas of Plato.