Did most people up until a couple centuries ago believe that the Earth was flat? Did Christopher Columbus encounter opposition from flat-earthers? Is the idea that the Earth is approximately spherical a discovery of “modern science”?
It may come as a surprise to many to learn that the answers to all three of those questions is a resounding, NO!
The ancient Greeks knew that the Earth was round and they had a pretty good estimate of how large it was (<5% error). One has to look really hard to find anyone of any significant stature during the Middle Ages who thought the world was flat.
The idea that the world was filled with flat-earthers a couple centuries ago is flat-out false, and was made-up in the late 19th century as part of an ongoing anti-religious polemic on the part of Darwinian naturalists and positivists.
See the link below for additional details.