Claudius Ptolemy

By Nicolas Henderson


Born c. AD 100, died c. AD 170 (aged 69-70)


Most of the facts pertaining to Ptolemy’s life are shrouded in mystery and there is no definitive record regarding his date of birth. Till today, whatever little is known of him comes from his works and some other historical findings. One thing is for sure that he was Greek by birth and was a citizen of Rome and therefore the name, Claudius (Roman), Ptolemy (Greek). Ptolemy’s major astrological text is the ‘Tetrabiblos Syntaxis’, meaning four books. In this book Ptolemy’s efforts to draw a more rational picture of the astrology of his days are evident. He offered a detailed framework on the subject which helped the practitioners of his time to be able to understand astrology both on scientific and religious grounds. The ‘Tetrabiblos’ is known to have "enjoyed almost the authority of a Bible among the astrological writers for a thousand years or more". Ptolemy’s reputation came along with his astronomical works. He recorded over 1000 stars, of which 300 were newly found. Also, he was responsible for the formation of the first practical theory of refraction of light. He discussed about the dimensions of the planets with much precision. The ‘Almagest’, an astronomical treatise by Ptolemy is a complete text on the ancient view of astronomy.


It is believed that Ptolemy died in around 168 AD. He was more than an astronomer. Till today, he is considered to be an important figure when the history of geography and cartography are recounted. Until Columbus came up with his map of the world, Ptolemy’s map was taken as the principal guide. Even the Ptolemaic view of the universe had dominated science for some centuries as Ptolemy successfully established his findings in the form of a theory and this theory actually worked. He was also able to calculate positions of the planets accurately.

Major contributions to astronomy:

  • Almagest
  • Tetrabiblos Syntaxis


"Claudius Ptolemy Biography." - Childhood, Life Achievements & Timeline. Web. 6 Jan. 2016.

"Claudius Ptolemy." Claudius Ptolemy. Web. 6 Jan. 2016.

"Ptolemy (ca. 100-ca. 170) -- from Eric Weisstein's World of Scientific Biography." Ptolemy (ca. 100-ca. 170) -- from Eric Weisstein's World of Scientific Biography. Web. 6 Jan. 2016.