|born||c. ad 100|
|died||c. ad 170 (aged 69–70)|alexandria
, egypt, roman empire
claudius ptolemy (/; koinē greek: Κλαύδιος Πτολεμαῖος, klaúdios ptolemaîos [kláwdios ptolɛmɛ́os]; latin: claudius ptolemaeus; c. ad 100 – c. 170) was a greek mathematician, astronomer, geographer and astrologer. he lived in the city of alexandria in the roman province of egypt, under the rule of the roman empire, had a latin name, which several historians have taken to imply he was also a roman citizen, cited greek philosophers, and used babylonian observations and babylonian lunar theory. the 14th-century astronomer theodore meliteniotes gave his birthplace as the prominent greek city ptolemais hermiou (greek: Πτολεμαΐς ‘Ερμείου) in the thebaid (greek: Θηβαΐδα [Θηβαΐς]). this attestation is quite late, however, and there is no other evidence to confirm or contradict it. he died in alexandria around ad 168.
ptolemy wrote several scientific treatises, three of which were of importance to later byzantine, islamic and western european science. the first is the astronomical treatise now known as the almagest, although it was originally entitled the mathematical treatise (Μαθηματικὴ Σύνταξις, mathēmatikē syntaxis) and then known as the great treatise (Ἡ Μεγάλη Σύνταξις, hē megálē syntaxis). the second is the geography, which is a thorough discussion of the geographic knowledge of the greco-roman world. the third is the astrological treatise in which he attempted to adapt horoscopic astrology to the aristotelian natural philosophy of his day. this is sometimes known as the apotelesmatika (Ἀποτελεσματικά) but more commonly known as the tetrabiblos from the greek (Τετράβιβλος) meaning "four books" or by the latin quadripartitum.