Birth of Ptolemy

Ptolemy was born in 100 CE in Ptolemais Hermiou. A Greek-speaking mathematician, astronomer and geographer who lived in Roman Alexandria, Ptolemy wrote works that dominated scientific thinking for well over a thousand years. His Almagest set out a geocentric model of the universe, with the planets moving on circles within circles called epicycles, and included a star catalogue. His Geography listed the coordinates of thousands of places and described methods for drawing maps. He also wrote on astrology, optics and music theory. His astronomy was preserved and refined by Islamic scholars and was later transmitted to medieval Europe, until it was replaced by the heliocentric system of Copernicus. The dates given for his life are approximate.

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