Historians of mathematica are indebted to the Neoplatonic philosopher and mathematician Proclus for his commentary on Euclid Book I, one of our principal sources of information on the early history of elemesatary geometry. Proclus had access to historieal and critical works now lost to us, chief of which were Eudemus' History of Geometry in four books and Geminus' apparently comprehensive Theory of the Mathematical Sciences. Proclus commentary on Plato's Republic also contain passages of interest to the historian of mathematica. Procus studied at Alexandria, became head of the Athenian school, and died in Athens in 485 when about 75 years old.