100 - 170

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Claudius Ptolemy (; Koinē Greek: Κλαύδιος Πτολεμαῖος, Klaúdios Ptolemaîos, [ˈklaw.di.os pto.lɛˈmɛ.os]; Latin: Claudius Ptolemaeus; c. 100 – c. 170 AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen 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 Mathēmatikē Syntaxis or Mathematical Treatise, and later known as The Greatest Treatise. The second is the Geography, which is a thorough discussion on maps and the geographic knowledge of the Greco-Roman world. Read more on Wikipedia

Since 2007, the English Wikipedia page of Ptolemy has received more than 4,136,608 page views. His biography is available in 109 different languages on Wikipedia (up from 107 in 2019). Ptolemy is the 4th most popular astronomer (up from 5th in 2019), the 4th most popular biography from Egypt (up from 7th in 2019) and the most popular Egyptian Astronomer.

Ptolemy is most famous for his geocentric model of the universe, which he proposed in his book, "Almagest." In this model, the earth is at the center of the universe and all other celestial bodies orbit around it.

Memorability Metrics

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  • 109

    Languages Editions (L)

  • 14.19

    Effective Languages (L*)

  • 3.84

    Coefficient of Variation (CV)

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Among astronomers, Ptolemy ranks 4 out of 532Before him are Galileo Galilei, Nicolaus Copernicus, and Giordano Bruno. After him are Johannes Kepler, Tycho Brahe, Anders Celsius, Edwin Hubble, Aristarchus of Samos, William Herschel, Ulugh Beg, and Hipparchus.

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Among people born in 100, Ptolemy ranks 1After him are Joseph of Arimathea, Pope Alexander I, Longinus, James the Less, Decebalus, Pope Hyginus, Pope Telesphorus, Dionysius the Areopagite, Saint Sarah, Pope Victor I, and Justin Martyr. Among people deceased in 170, Ptolemy ranks 1After him are Apuleius, Salvius Julianus, and Junius Rusticus.

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In Egypt

Among people born in Egypt, Ptolemy ranks 4 out of 520Before him are Moses (-1393), Tutankhamun (-1341), and Nefertiti (-1400). After him are Akhenaten (-1400), Euclid (-350), Hypatia (350), Cleopatra (-69), Yasser Arafat (1929), Hatshepsut (-1507), Joshua (-1355), and Origen (185).


Among astronomers born in Egypt, Ptolemy ranks 1After him are Sosigenes of Alexandria (-80) and Timocharis (-320).