The World by Eratosthenes. 1886 replica of a map of the known world according to the Ancient Greek geographer, mathematician and astronomer Eratosthenes (276 to 194 BC). Eratosthenes was the first to calculate the circumference of the Earth (c 240BC) achieving an accuracy of better than 2 per cent. He also computed the distances of the Earth from the Moon and the Sun, and accurately measured the angle of the ecliptic. His system of calculating prime numbers is known as 'Eratosthenes' Sieve'. He established the discipline of geography, developed a system of latitude and longitude, and produced a star catalogue, as well as producing this map of the known world.