Eratosthenes was a native of Cyrene on the south coast of the Mediterranean Sea and was only a few years younger than Archimedes. He spent many years of his early life in Athens and, when about forty, was invited by Ptolemy III of Egypt to come to Alexandria as tutor to his son and to serve as chief librarian at the University there. It is told that in old age, about 194 B.C., he became almost blind from ophthalmia and committed suicide by voluntary starvation.