Claudius Ptolemaeus, commonly known as Ptolemy, was a prolific scientist, astronomer, and mathematician known for his work on the geocentric model of the universe. Some of the synonyms used to refer to him include Claudius Ptolemy, Ptolemeus, Ptolomaeus, and Ptolomeus. Other variations include Ptolemeo, Ptolemei, Ptolemeios, and Ptolemaios. Regardless of the spelling or variation, Ptolemy's contributions to astronomy have been significant in the development of scientific knowledge in the ancient world and beyond. Today, his writings and theories continue to influence the scientific community, particularly in the fields of astronomy, mathematics, and geography.