The idea that the earth is round has not been a matter of controversy since the days of the Ancient Greeks.

The notion of a flat earth is a pretty modern one.Washington Irving wrote a story about Christopher Columbus in 1828 in which he had the sailor worried about falling of the edge of the Earth, and the idea attracted some support later in the century.

No shortage of things you can knock the Church for in 2000 years, but flat earthism is not one of them.