Oh, nobody ever really believed the Earth was flat. The Greeks
   knew it. The knowledge passed on through Byzantium unchanged.
   Even in Medieval Europe they knew the Earth was round, except
   for a few decorative maps and creative works.

   There was no Dark Ages. That concept came from Petrarch in the
   1330s and he was criticizing architecture.

   Over the centuries its use has expanded and grown, and we were
   thrown into three hundred years of stupidity up through the mid
   1950s where we actually believed people were once stupid, then
   enlightened.

   Now historians know better, but the myth carries on.