Eratosthenes was an Ancient Greek scientist born in the town of Cyrene, which is no in Libya, in about 276 BC. He was famous as a mathematician and geographer.
Eratosthenes produced a reliable, logical method to discover prime numbers. It’s known as the sieve of Eratosthenes, and is still important in modern number theory in an updated form.
Assuming that the earth was a sphere, Eratosthenes calculated its size with good accuracy. He also calculated the tilt of earth’s axis fairly accurately. Eratosthenes produced the first map of the world which used meridian lines and parallel lines. These were similar to our modern lines of latitude and longitude. This great scientist can be said to have invented geography
In fact, today we still use the word he invented for this new discipline. ‘Geo’ was Greek for ‘Earth’ and ‘graphy’ meant ‘field of study.’
Eratosthenes also wrote books on philosophy, mathematics, astronomy, history, comedy, and poetry. His all-round knowledge made him the ideal choice for the most prestigious job an academic could enjoy in Ancient Greece. He was the director of the library of Alexandria, the greatest intellectual institution of the ancient world.