Stone to Silicon

Math & science · c. 150 CE

Ptolemy's Almagest

A geocentric model with epicycles predicts planetary positions for 1,400 years.

Claudius Ptolemy's 13-book synthesis of Greek astronomy included a star catalogue of 1,022 stars and full chord tables. Its accuracy made it the reference that Islamic and European astronomers corrected and eventually overturned.

See it in the living treeWikipedia

Arcs above join it to what it stood on, arcs below to what it led to. The bar places this stretch on the tree's whole timeline.

What it built on 1

What it led to 2