Ptolemaeus

Ptolemaeus, also known as Claudius Ptolemy, was a Greco-Roman mathematician, astronomer, and geographer of the 2nd century AD, best remembered for his geocentric model of the universe, which posited that the Earth was the center of the cosmos. His influential work, the 'Almagest', compiled and systematized the astronomical knowledge of his time, introducing concepts such as epicycles to explain the complex movements of celestial bodies. Ptolemy's geocentric theory dominated astronomical thought for over a millennium until the heliocentric model proposed by Copernicus challenged its validity.