Theon of Alexandria Theon of Alexandria Theon of Alexandria (; ; 335 – c. 405) was a Greek scholar and mathematician who lived in Alexandria, Egypt. He edited and arranged Euclid's "Elements" and wrote commentaries on works by Euclid and Ptolemy. His daughter Hypatia also won fame as a mathematician. Little is known about the life of Theon. He made predictions and observances of solar and lunar eclipses in 364 which show he was active at that time, and he is said to have lived during the reign of Theodosius I (379–395). The biographical tradition of the tenth century Byzantine "Suda" defines Theon
Library of Alexandria BC, however, Aristarchus became caught up in a dynastic struggle in which he supported Ptolemy VII Neos Philopator as the ruler of Egypt. Ptolemy VII was murdered and succeeded by Ptolemy VIII Physcon, who immediately set about punishing all those who had supported his predecessor, forcing Aristarchus to flee Egypt and take refuge on the island of Cyprus, where he died shortly thereafter. Ptolemy VIII expelled all foreign scholars from Alexandria, forcing them to disperse across the Eastern Mediterranean. Ptolemy VIII Physcon's expulsion of the scholars from Alexandria brought about a shift in the history of Hellenistic scholarship. The scholars