Conversation so far:
What was Eratosthenes greatest achievement?
Eratosthenes is best known for being the first person to calculate the circumference of the Earth, which he did by comparing angles of the mid-day Sun at two places.
Did Eratosthenes think the sun revolves around the Earth?
No
Did Eratosthenes map the moon?
No

Question: Did he teach other Greek Philosophers?
Self-contained rewrite: Did Eratosthenes teach other Greek Philosophers?