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
Lighthouse of Alexandria Lighthouse of Alexandria The Lighthouse of Alexandria, sometimes called the Pharos of Alexandria (; Ancient Greek: ὁ Φάρος τῆς Ἀλεξανδρείας, contemporary Koine ), was a lighthouse built by the Ptolemaic Kingdom, during the reign Ptolemy II Philadelphus (280–247 BC) which has been estimated to be in overall height. One of the Seven Wonders of the Ancient World, for many centuries it was one of the tallest man-made structures in the world. Badly damaged by three earthquakes between AD 956 and 1323, it then became an abandoned ruin. It was the third longest surviving ancient wonder (after the Mausoleum at Halicarnassus