Occupation and discoveries
Claudius Ptolemy was an astronomer, astrologer, geographer and mathematician. He wrote a lot of astronomy books, one of them is called Almagest and is the only surviving detailed ancient written work on astronomy. He created the 'Ptolemaic System' which is a model of the universe where Earth is at the center. He also cataloged 1028 stars and gave formations their traditional Greek and Roman names that are still used today. He wrote a book 'Geographia' that had detailed maps of the world and was used by travelers for hundreds of years.
There isn't a lot of reliable information about Claudius's life. He was a Roman citizen but was believed to be Greek. He lived in Alexandria. His birthplace was given as Ptolemais Hermiou by a 14th century astronomer called Theodore Meliteniotes but this was never proven. He died in Alexandria around AD 168.