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
Greek Orthodox Patriarchate of Alexandria and all Africa Greek Orthodox Patriarchate of Alexandria and all Africa The Greek Orthodox Patriarchate of Alexandria and all Africa (Greek: , "Patriarcheîon Alexandreías kaì pásēs Aphrikês") is an autocephalous Byzantine Rite jurisdiction of the Eastern Orthodox Church, having the African continent as its canonical territory. It is commonly called the "Greek" or "Eastern" Orthodox Patriarchate of Alexandria to distinguish it from the "Coptic" or "Oriental" Orthodox Patriarchate of Alexandria. Members of the Greek Orthodox Patriarchate were once known as Melkites, because they remained in communion with the Ecumenical Patriarchate of Constantinople after the schism that followed the Council of Chalcedon in 451.