Claudius Ptolemy (; , "Klaúdios Ptolemaîos" ; ; ) was a Greco-Roman mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in the city of Alexandria in the Roman province of Egypt, wrote in Koine Greek, and held Roman citizenship. The 14th-century astronomer Theodore Meliteniotes gave his birthplace as the prominent Greek city Ptolemais Hermiou () in the Thebaid (). This attestation is quite late, however, and, according to Gerald Toomer, the translator of his "Almagest" into English, there is no reason to suppose he ever lived anywhere other than Alexandria. He died there around AD 168. 

Ptolemy wrote several scientific treatises, three of which were of importance to later Byzantine, Islamic and European science. The first is the astronomical treatise now known as the "Almagest", although it was originally entitled the "Mathematical Treatise" (, "Mathēmatikē Syntaxis") and then known as the "Great Treatise" (, "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" () but more commonly known as the "Tetrabiblos" from the Greek () meaning "Four Books" or by the Latin "Quadripartitum".
When did Ptolemy die?
around AD 168