Portrait of Eratosthenes

Eratosthenes

Greek mathematician, geographer, poet, astronomer, librarian and music theorist

Lived
275 BC–193 BC

Updated September 2026

About Eratosthenes

Eratosthenes of Cyrene was an Ancient Greek polymath: a philosopher, scholar, mathematician, geographer, poet, astronomer, and music theorist. Eratosthenes eventually became the chief librarian at the Library of Alexandria. His work was the precursor to the modern discipline of geography, and he introduced some of its terminology, coining the terms geography and geographer.

Biography from Wikipedia, CC BY-SA 4.0. Photo via Wikimedia Commons.

Sources: book lists and dates from Wikidata and Open Library, ratings from Open Library readers. Last updated September 2026.