Ptolemy

The preeminent ancient astronomer, geographer, and astrologer; his Almagest provided the mathematical foundation for the geocentric model of the universe that dominated Western and Islamic astronomy for 1,400 years; his Geography provided the coordinate system for European cartography through the Renaissance; his Tetrabiblos systematized ancient astrology.

The Almagest's mathematical models of planetary motion using epicycles were accurate enough to predict astronomical events for over a millennium; the Ptolemaic geocentric system became the astronomical paradigm until Copernicus; his Geography established latitude/longitude coordinate mapping of the known world that shaped cartography through the Age of Discovery.