PTOLEMY

flourished AD 127, 145, Alexandria Latin in full Claudius Ptolemaeus ancient astronomer, geographer, and mathematician who considered the Earth the centre of the universe (the Ptolemaic system). Virtually nothing is known about his life. Additional reading There is no biography of Ptolemy. His astronomical work is described in some detail in J.L.E. Dreyer, A History of the Planetary Systems from Thales to Kepler (1905; republished as A History of Astronomy, 2nd ed., 1953). A full English text of Almagest which, incidentally, shows how clearly Ptolemy expressed himself, is the translation by R. Catesby Taliaferro published in Great Books of the Western World, vol. 16 (1952). Ptolemy's geographical work is discussed by J.O. Thomson in History of Ancient Geography (1948); and his mathematics in Thomas L. Heath, A Manual of Greek Mathematics (1931, reprinted 1963). Ptolemy's work is also described in the context of early astronomy as it leads to modern times in Colin A. Ronan, Discovering the Universe (1971), which is a more popular text.