Claudius Ptolemy (; Ancient Greek: Πτολεμαῖος, Ptolemaios; Latin: Claudius Ptolemaeus; c. 100 – c. 170 AD) was an Alexandrian mathematician, astronomer, astrologer, geographer, and music theorist who wrote about a dozen scientific treatises, three of which were important to later Byzantine, Islamic, and Western European science. The first was his astronomical treatise now known as the Almagest, originally entitled Mathematical Treatise (Greek: Μαθηματικὴ Σύνταξις, Mathēmatikḗ Syntaxis).
https://en.wikipedia.org/wiki/Ptolemy