Ptolemy also wrote an influential work, Harmonics, on music theory.
The maps look distorted compared to modern maps because Ptolemy's data were inaccurate.
Following Aristotle, Ptolemy and those who accepted his view made a number of philosophical assumptions underlying their cosmology.
Ptolemy followed that tripartite division, claiming that theology is the branch of theoretical philosophy that investigates the first cause of the first motion of the universe (Taub 1993).
A second of Ptolemy's influential works is his Geographia, a thorough discussion of the geographic knowledge of the Greco-Roman world.
So Ptolemy saw astrology as something to be used in life but in no way relied on entirely.
Ptolemy's astronomical interests also appeared in a discussion of the music of the spheres.
Ptolemy also wrote that Aristotle had divided theoretical philosophy into three branches: physics, mathematics, and theology.
Ptolemy's geocentric model or theory put the Earth at the center of the universe—a theory often known as the Ptolemaic System, or Ptolemaic Cosmology.
One reason is that Ptolemy underestimated the size of the Earth—while Eratosthenes found 700 stadia for a degree on the globe, in the Geographia Ptolemy used 500 stadia.
Aristotle—the only philosopher to whom Ptolemy refers explicitly—had distinguished between practical and theoretical philosophy, and Ptolemy used that distinction, noting that education is needed for theoretical philosophy but not for practical philosophy.
Ptolemy's achievement was to order his material in a systematic way, showing how the subject could, in his view, be rationalized.
Ptolemy was a first-rate geometer and mathematician who devised important new geometrical proofs and theorems.
Ptolemy was well aware that he knew about only a quarter of the globe, and he knew that his information did not extend to the Eastern Sea.
Ptolemy was the author of numerous scientific treatises, at least three of which were of continuing importance to later Islamic and European science.
Aside from that, almost nothing is known about Ptolemy's life, family background, or physical appearance.
Another of Ptolemy's noteworthy works is his treatise on astrology known as the Tetrabiblos ("Four books", derived from the Greek words tetra, meaning "four", and biblos, meaning "book").
Latitude was measured from the equator, as it is today, but Ptolemy preferred to express it as the length of the longest day rather than degrees of arc.
Recent attention to Ptolemy's Optics shows its "sophisticated observational basis" and that Ptolemy had conducted "a series of carefully contrived experiments measuring refraction from air to water, air to glass, and water to glass."
The maps in surviving manuscripts of Ptolemy's Geographia, however, date only from about 1300, after the text was rediscovered by Maximus Planudes.
Ptolemy also devised and provided instructions on how to create maps of the whole inhabited world (oikoumenи) as well as the Roman provinces.
Ptolemy gave various reasons why the Earth must be both at the center of the universe and immovable.
Both Ptolemy and Aristotle held theology to be one of the main branches of philosophy.
Ptolemy was an astronomer and mathematician. He believed that the Earth was the center of the Universe. The word for earth in Greek is geo, so we call this idea a "geocentric" theory.
The earliest, and perhaps most important of Ptolemy's work that has survived is the Almagest, a treatise in 13 books. It gives in detail the mathematical theory of the motions of the Sun, Moon, and planets. Ptolemy made his most original contribution by presenting details for the motions of each of the planets.
From the Greek name Πτολεμαιος (Ptolemaios), derived from Greek πολεμηιος (polemeios) meaning "aggressive, warlike". Ptolemy was the name of several Greco-Egyptian rulers of Egypt, all descendants of Ptolemy I, one of the generals of Alexander the Great. This was also the name of a Greek astronomer.
Claudius Ptolemy (about 85–165 CE) lived in Alexandria, Egypt, a city established by Alexander the Great some 400 years before Ptolemy's birth. ... Ptolemy was the only great astronomer of Roman Alexandria. Ptolemy was also a mathematician, geographer, and astrologer.
Ptolemy. Ptolemy, Latin in full Claudius Ptolemaeus, (born c. 100 ce—died c. 170 ce), an Egyptian astronomer, mathematician, and geographer of Greek descent who flourished in Alexandria during the 2nd century ce. ... Ptolemy's theory of the solar system.
Ptolemaic system. n. The astronomical system of Ptolemy, in which the earth is at the center of the universe with the sun, moon, planets, and stars revolving about it in circular orbits at increasing distance. Some of the orbits have epicycles.
The only object whose shadow is always circular is a sphere. (2) Greek astronomers developed a geocentric (Earth-centered) model for the universe. (3) Ptolemy used epicycles to explain the retrograde motions of planets.
When her father Ptolemy XII died in 51 BC, Cleopatra became co-regent with her 10-year-old brother Ptolemy XIII. They were married, in keeping with Egyptian tradition.