Antiquity's two greatest scientists were pen pals
Archimedes, working in Syracuse, addressed one of his most remarkable treatises — The Method — as a letter directly to Eratosthenes, the polymath who ran the Library of Alexandria and had famously measured the size of the Earth. Its preface opens “Archimedes to Eratosthenes: Greetings,” and goes on to reveal his private technique for discovering theorems, sent across the Mediterranean to a fellow mathematician whose judgment he prized.
How we know
Archimedes of Syracuse (c.287–212 BCE) and Eratosthenes of Cyrene (c.276–194 BCE) were contemporaries. Archimedes' treatise 'The Method of Mechanical Theorems' takes the form of a letter addressed to Eratosthenes, recovered from the Archimedes Palimpsest (identified by Heiberg in 1906).
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