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 who had studied at the Library of Alexandria and their students continued to conduct research and write treatises, but most of them no longer did so in association with the Library of Alexandria. A diaspora of Alexandrian scholarship occurred, in which scholars dispersed first throughout the eastern Mediterranean and later throughout the western Mediterranean as well. Aristarchus's student Dionysius Thrax ( 170– 90 BC) established a school on the Greek island of Rhodes. Dionysius Thrax wrote the first book on Greek grammar, a succinct guide to speaking and writing clearly and effectively. This book remained the primary grammar textbook for