Greek mathematics from the sixth century BC to the fourth century AD is represented by works of Pythagoras, Proclus, Thales, Democritus, Hippocrates of Chios, Theaetetus, Plato, Eudoxus of Cnidus, Aristotle, Euclid, Eratosthenes, Apollonius, Ptolemy, Heron of Alexandria, Diophantus, and Pappus.