World History: AD 150s

c. AD 150 · Africa · Science

Ptolemy's Almagest

The Almagest is a 2nd-century mathematical and astronomical treatise on the apparent motions of the stars and planetary paths, written by Claudius Ptolemy in Koine Greek. One of the most influential scientific texts in history, it canonized a geocentric model of the Universe that was accepted for more than 1,200 years from its origin in ancient Greece, through to the medieval Byzantine and Islamic worlds, and in Western Europe through the Middle Ages and early Renaissance until the Scientific Revolution. It is also a key source of information about ancient Greek astronomy.