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
Ptolemy X Alexander I throne, and replacing the former sarcophagus with one made of glass. The citizens of Alexandria were so outraged at this act that they exiled him again almost immediately and attempted to wipe out all record of him. He would later be killed on his way to Cyprus. When Ptolemy X died, Ptolemy IX regained the throne. When Ptolemy IX died in 81 BC, Ptolemy X's wife Berenice III took over the throne for six months. Ptolemy X Alexander I Ptolemy X Alexander I (, "Ptolemaĩos Aléxandros") was King of Egypt from 110 BC to 109 BC and 107 BC till