Ptolemaic system

Ptolemaic model

Although the basic tenets of Greek geocentrism were established by the time of Aristotle, the details of his system did not become standard. The Ptolemaic system, written down by the Hellenistic astronomer Claudius Ptolemaeus in the 2nd century AD, finally standardized geocentrism. The key work describing the system only survives via an Arabic translation of a book named Planetary Hypothesis. For over a millennium, European and Islamic astronomers assumed it was the correct cosmological model. Because of its influence, people sometimes wrongly think the Ptolemaic system is identical with the geocentric model.