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 Philadelphus (son of Cleopatra) Ptolemy Philadelphus (son of Cleopatra) Ptolemy Philadelphus (, "Ptolemy the brother-loving", August/September 36 BC – 29 BC) was a Ptolemaic prince and was the youngest and fourth child of Greek Ptolemaic Queen Cleopatra VII of Egypt, and her third with Roman Triumvir Mark Antony. Ptolemy was of Greek and Roman heritage. He was born in Antioch, Syria (now a part of modern Turkey). Ptolemy was named after the original Ptolemy II Philadelphus (the second Pharaoh of the Ptolemaic dynasty) and Cleopatra's intention was recreating the former Ptolemaic Kingdom. In late 34 BC, at the Donations of Alexandria, Ptolemy was made