Ptolemy completes the Almagest
- Date
- c. 150 CE
- Category
- Science, technology & invention
- Region
- Roman Egypt (Alexandria)
- Era
- Classical Antiquity
- Significance
Around 150 CE, Claudius Ptolemy of Alexandria completed the Mathematike Syntaxis, known later by its Arabic-derived title the Almagest ('the greatest').
In thirteen books it presented a comprehensive geocentric model of the cosmos, with the Earth fixed at the centre and the Sun, Moon, planets and stars carried on combinations of circles - deferents, epicycles and equants - that reproduced observed motions with impressive accuracy. The work supplied the trigonometry, a star catalogue of over a thousand stars, and the predictive tables that astronomers needed. Translated into Arabic in the 8th-9th centuries and into Latin in the 12th, the Almagest dominated astronomy in the Islamic world and Europe for roughly 1,400 years, until the heliocentric models of Copernicus and Kepler displaced it. It remains the most influential astronomical text of antiquity and a model of mathematically grounded science.
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Empires active in c. 150 CE
- Roman Empire27 BCE – 476 CE
- Han Dynasty202 BCE – 220 CE
- Kingdom of Funan50 CE – 550 CE
- Zapotec State of Monte Albán500 BCE – 800 CE
- Kushan Empire30 CE – 375 CE
- Parthian Empire247 BCE – 224 CE
Related science, technology & invention events
- Cai Lun standardises papermaking105 CE
- Zhang Heng invents the seismoscope132 CE
- Compilation of the Charaka Samhita and the Codification of Ayurvedac. 100 CE
- Inauguration of the Colosseum (Flavian Amphitheatre)80 CE
- The Bakhshali manuscript and the earliest recorded zeroc. 224–383 CE (carbon-dated)
- Earliest securely dated Maya/Mesoamerican Long Count inscription36 BCE (Long Count 7.16.3.2.13)
Further reading
The wider story
A Little History of Science
Warm, jargon-free tour of discovery from Babylonian stargazers to the genome.
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