Who is Potolmy and what did he do?

Ptolemy was a Greco-Roman mathematician, astronomer, and geographer who lived in Alexandria, Egypt, during the 2nd century AD. He is best known for his work "Almagest," which presented the geocentric model of the universe, positing that the Earth is at the center of the universe and all celestial bodies revolve around it. Ptolemy also made significant contributions to geography, most notably with "Geographia," which compiled knowledge of the world and introduced the use of coordinates for mapping locations. His works influenced both Islamic and European astronomy for many centuries.