“Beware of false knowledge”, George Bernard Shaw wrote, “it is more dangerous than ignorance”. Every year I would walk into the classroom of one of my courses and write with capital letters on the board the following statement: “Because of the Church people in the Middle Ages believed in the flat earth“. Then, I would turn to students and ask them to raise their hands if they agree with that statement. The last time I did that, all hands went up. I asked them why do they think that. Their answer? “Well, we heard it somewhere, or maybe even read it or saw it on TV. We are not entirely sure! It doesn’t matter! It’s a well-known fact, right?!”. It isn’t! Actually, I think this is the most popular misconception regarding the history of the Catholic Church. It goes hand in hand with the overall theory about the historical conflict between science and Christianity. But, that’s another topic. Let’s get back to flat-earth nonsense.

Catholic Church never supported the “flat-earth theory”. Not even close. First of all, since the time of Aristotle, people knew that the earth wasn’t flat. Every major Greek philosopher thought that the earth was a sphere: Pythagoras, Plato, Aristotle, Euclid, etc. When Christianity came along, this idea didn’t vanish! Quite the contrary, early Church fathers asserted spherical earth: St. Ambrose, Origen, John Chrysostom, Gregory of Nyssa. All of the influential medieval theologians and philosophers agreed upon this as well! So, where did this idea come from? In fact, there were two flat-earth proponents in the history of the Church: Lactantius (265 – 345 CE), and Cosmas Indicopleustes (c. 540 CE). However, they were essentially unknown in the Middle Ages. For example, Cosmas’ work was translated into Latin for the first time in 1706! It was never translated into Latin during the Middle Ages. Moreover, Lactantius was pretty much ignored (because the church had declared his works heretical) all the way to Nicholas Copernicus (1473 – 1543) who does refer to Lactantius’s “scientific” views. However, he clearly presents them as the minority opinion. Nevertheless, nineteenth-century scientists such as John W. Draper, determined upon demonizing the Church’s role in the history of science and diminishing the Middle Ages as a time of superstition and decay, portrayed Lactantius’ work as central and influential.

P.S. There is an excellent book by Jeffrey B. Russell entitled Inventing the Flat Earth:
Columbus and Modern Historians published back in 1991. In it, Russell gives a detailed account of medieval ideas about the earth and cosmos. He also traces the history of this myth that seems to be around still today! If you are not up to that kind of literature, I can recommend a short article by my friend Ante Vučić written in Croatian (see: here).