who was the first to measure the earth circumference
Eratosthenes Eratosthenes of Cyrene (/ɛrəˈtɒsθəniːz/; Greek: Ἐρατοσθένης ὁ Κυρηναῖος, IPA: [eratostʰénɛːs]; c. 276 BC[1] – c. 195/194 BC[2]) was a Greek mathematician, geographer, poet, astronomer, and music theorist. He was a man of learning, becoming the chief librarian at the Library of Alexandria. He invented the discipline of geography, including the terminology used today.[3]