Ptolemy, Greek astronomer and geographer, c 130 AD.
© Science Museum / Science & Society Picture Library
Ptolemy of Alexandria (c 90-168 AD) observing with a quadrant, with the goddes Astronomia behind him. Ptolemy was probably born in Egypt but produced his works 'Almagest' (c 150 AD) and 'Geographia' in Greece. His famous summary of Greek astronomical ideas and his theories of the universe dominated western ideas on astronomy and geography until the time of Copernicus (1473-1543), fourteen centuries later. The Ptolemaic system put the Earth at the centre of the universe with the planets revolving around it. Illustration from the 1535 edition of the philosopher Gregor Reisch's (1467-1525) 'Margarita Philosophica' ('Pearl of Wisdom'), an encyclopedia compiling commentaries on subjects including astronomy, geometry, anatomy and geography.