Eratosthenes (Greek ; 276 BC - 194 BC) was a Greek mathematician, geographer and astronomer. His contemporaries nicknamed him "beta" (Greek for "number two") because he supposedly proved himself to be the second in the ancient Mediterranean region in many fields. He is noted for devising a system of latitude and longitude, and for being the first known to have calculated the circumference of the Earth. He also made what he thought was a map of the Earth. Wikipedia
The definitive Wikipedia entry for Eratosthenes. Wikipedia is the biggest multilingual free-content encyclopedia on the Internet. en.wikipedia.org/wiki/Eratosthenes
