 Xenocrates (of Chalcedon, a city on the Asian side of the Bosporus opposite Byzantium, according to Diogenes Laertius (D.L.) iv 14), became head of the Academy after Speusippus died, in 339/338 (“in the second year of the 110th Olympiad”). D.L. says he held that position for twenty-five years, and died at 82. So his dates work out to 396/395–314/313.