I believe that Eratosthenes, the third Librarian of Alexandria, lived from 276 to 194 B.C.
He knew good and well that the world was roughly spherical, and he calculated the circumference of the Earth with reasonable accuracy.
Humans have known that the world was not flat for a long, long time. Columbus certainly knew it -- he just misunderstood (underestimated) how big the Earth was, due to a simple error.
When Columbus sailed for "India" nobody who wasn't ignorant feared that he would fall off the edge of the Earth.
He knew good and well that the world was roughly spherical, and he calculated the circumference of the Earth with reasonable accuracy.
Humans have known that the world was not flat for a long, long time. Columbus certainly knew it -- he just misunderstood (underestimated) how big the Earth was, due to a simple error.
When Columbus sailed for "India" nobody who wasn't ignorant feared that he would fall off the edge of the Earth.