Eratosthenes calculated the circumference of the Earth about 220BC, he was out by <50 miles on the modern accepted value. He pre-dated Copernicus by a mere 150

Eratosthenes calculated the circumference of the Earth about 220BC, he was out by <50 miles on the modern accepted value. He pre-dated Copernicus by a mere 1500 years. Educated people have known for a long time that the earth is spherical is what I'm getting at, For many hundreds/thousands of years what the educated class knew and what the rest of society knew was often wildly divergent - as you'd expect in a society with no formal education system where only the wealthy or the sons of the wealthy could afford to spend the time educating themselves/tinkering.