The flat Earth model is an archaic conception of Earth's shape as a plane or disk. Many ancient cultures subscribed to a flat Earth cosmography, including Greece until the classical period (323 BC), the Bronze Age and Iron Age civilizations of the Near East until the Hellenistic period (31 BC), India until the Gupta period (early centuries AD), and China until the 17th century.
The idea of a spherical Earth appeared in ancient Greek philosophy with Pythagoras (6th century BC), although most pre-Socratics (6th–5th century BC) retained the flat Earth model. In the early 4th century BC Plato wrote about a spherical Earth, and by about 330 BC his former student, Aristotle, had provided strong empirical evidence for this. Knowledge of the Earth's global shape then gradually began to spread beyond the Hellenistic world
Despite the scientific fact of Earth's sphericity, pseudoscientific flat Earth conspiracy theories are espoused by modern flat Earth societies and, increasingly, by unaffiliated individuals using social media.