That ain't what science believed on the whole though, was it.
In fact it was so pervasive that even the church accepted it.
And when they took the position against Galileo, everyone got to wear egg - save for Galileo. Truth is unpopular and usually held in a very small minority - sometimes of one or two. It is usually persecuted and rarely is accepted without a big fight. Who you kiddin.
Your mis-information is virtually complete, sweeping as it does across several different fields of knowledge. Galileo's problem with the church was over the solar system, not the shape of the earth. If you're at all curious, I have some useful Galileo links at my homepage.
Science, as we know it, didn't really get its start until the 16th century. As for the idea of the Earth being flat, the Church took that position because that is what Scripture implied; folks who actually studied and were learned for their period knew the Earth was a sphere from classical times.