Theodorus
31. Of CYRENE, a Pythagorean philosopher of the age of Pericles. According to Proclus (In Euclid. Element. Lib. I. Commentarius, lib. ii. p. 19, ed. Gryn. fol. Basil. 1533), he was a little younger than Anaxagoras [ANAXAGORAS], and was eminent as a mathematician. Apuleius (De Dogmate Platonis, lib. i. s. De Philos. Natural. haud longe ab init., and Diogenes Laertius (3.6, comp. 2.103) state that Plato went to Cyrene to study geometry under Theodore the mathematician, apparently the subject of this article. He is one of those enumerated by lamblichus (De Pythag. Vita, c. ult.) in his catalogue of the eminent Pythagoreans. (Fabric. Bibl. Graec. vol. i. p. 876, vol. x. p. 385.)
From William Smith (ed.), Dictionary of Greek and Roman Biography and Mythology. Text provided under a CC BY-SA license by Perseus Digital Library, http://www.perseus.tufts.edu, with funding from the National Endowment for the Humanities and Tufts University. Data accessed from https://github.com/PerseusDL/canonical-pdlrefwk/ on 17 October 2026.