Claudius, a celebrated mathematician and astrologer, was born at Pelusium, and furred by the Greeks Moft Divine and Moft Wise. He flourished at Alexandria in the second century, under the reigns of Adrian and Marcus Aurelius, about the 138th year before the Christian era. There are still extant his Geography, and several learned works on astronomy. The principal of which are, 1. The Almagest; 2. De Judiciis Astrologici; 3. Planisphaerium. His system of the world was for many years adopted by the philosophers and astronomers; but the learned have rejected it for the system of Copernicus. See Astronomy, n° 16.