Ptolemy

Claudius Ptolemy (; , ; ; – 160s/170s AD), better known mononymously as Ptolemy, was a Greco-Roman 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'). The second is the Geography, which is a thorough discussion on maps and the geographic knowledge of the Greco-Roman world. The third is the astrological treatise in which he a

theorem

2nd century Greco-Roman map of the world

lunar impact crater

dated list of kings used by ancient astronomers to date astronomical phenomena; preserved by the astronomer Ptolemy

inequality relating the six distances between four points on a plane

mathematical problem in geometrical optics

German cartographer (1420–1490)

name used for the Malay Peninsula by Greek and Roman geographers in classical antiquity, most famously in Claudius Ptolemy's 2nd-century Geography

2nd century Greek geographer and cartographer

2nd century CE trigonometric table

thumb|Interlinear Greek–Latin text from a 15th-century manuscript thumb|Start of the Arabic text thumb|Hugo of Santalla's Latin translation of Ahmad ibn Yusuf's commentary The Centiloquium ("one hundred sayings") is a Pseudo-Ptolemaic collection of one hundred aphorisms about astrology and astrological rules. It is first recorded at the start of the tenth century CE, when a commentary was written on it by the Egyptian mathematician Ahmad ibn Yusuf al-Misri (later sometimes confounded with his namesake Ali ibn Ridwan ibn Ali ibn Ja'far al-Misri, who lived a century later and wrote a commentary