No, they did not. Though the common perception is that Christopher Columbus had to convince King Ferdinand and Queen Isabella that the world was a sphere, Columbus actually had to convince the King and Queen of the circumference of the world. Though the ancient Greeks had discovered that the Earth was a sphere, centuries passed before this was generally accepted. By the fifteenth century, however—the time of Columbus’s sailing—most educated people believed the world to be round. But the question remained: how far was it to travel around the world?