Ancient sources Diogenes Laërtius, Lives of the Eminent Philosophers. Plato, Apology, Crito, Euthydemus, Phaedo. Xenophon, Memorabilia, Symposium. Modern sources Will Durant, The Story of Philosophy: the Lives and Opinions of the Greater Philosophers, New York, Simon & Schuster, 1926–1933. Debra Nails, The People of Plato, Indianapolis and Cambridge, Hackett Publishing, 2002. 5th-century BC Athenians Pupils of Socrates