Ptolemy
Ptolemy (fl. 2nd century AD). Egyptian astronomer. He maintained that the earth was at the centre of the universe and that the planets, sun, and stars moved around it, attached to concentric crystalline spheres. This system was accepted by the Christian Church and not challenged until 1543, when Copernicus put forward a system stating that the sun was at the centre of the universe. Ptolemy also wrote treatises on optics, geometry, and music, as well as a famous (if inaccurate) Guide to Geography. Ptolemy dynasty. Macedonian kings of Egypt (323-30 BC). Ptolemy I, one of Alexander the Great’s generals, seized Egypt after Alexander’s death. He went on to conquer Palestine, Cyprus; and part of Asia Minor and made Alexandria his capital. Ptolemy II, also known as Ptolemy Philadelphus, was the son of Ptolemy I. Successful in war, he also founded the famous museum and library of Alexandria and was a great patron of learning. Not all of the Ptolemies were equally able or successful, although the women of the dynasty, such as Cleopatra, were often outstanding personalities. The Ptolemies adopted Egyptian customs, including the authorization of marriage between brother and sister, and there were constant intrigues within the dynasty and warfare with neighbouring states. After 80 BC the Ptolemies became subject to Rome. Ptolemy XIII, the son of Caesar and Cleopatra and the last of the dynasty, was killed in 30 BC.
