Claudius Ptolemy


Claudius Ptolemy (c. 100 to c. 170 CE) was an Alexandrian mathematician, astronomer, and geographer. His works survived antiquity and the Middle Ages intact, and his theories, particularly on a geocentric model of the universe with planets following orbits within orbits, were hugely influential until they were replaced by the heliocentric model of the universe proposed by Copernicus and Galileo.

More about: Claudius Ptolemy


  • c. 100 CE - c. 170 CE
    Life of the Alexandrian astronomer and geographer Claudius Ptolemy.
  • c. 150 CE - 1150 CE
    Claudius Ptolemy publishes Almagest, which becomes the primary book on astronomy.