Colinxy: The Myth of Medieval Flat Earthers — And the Modern Politicians Who Repeat It

In 2012, the then–U.S. President Barack Obama mocked his Republican opponents as “Medieval Flat Earthers.” It was meant as a clever ad hominem — a way of dismissing dissenters as ignorant without engaging their arguments. Ironically, the phrase revealed a certain ignorance on his own part. He repeated a similar line in 2013, this time dropping the “medieval” but keeping the caricature.

The problem is simple: the idea that people in the Middle Ages believed in a flat Earth is a modern myth. It’s been a convenient rhetorical prop for decades, especially in popular culture. Ridley Scott’s 1492: Conquest of Paradise famously portrays Christopher Columbus as a lone visionary trying to convince a benighted world that the Earth is round — a theme Obama echoed. It makes for good cinema, but terrible history.

The Round Earth Was Old News Before Christ Was Born

The spherical Earth was not a controversial idea in the Middle Ages because it had already been demonstrated in the Classical world. Eratosthenes of Cyrene — a Greek mathematician, geographer, and polymath — calculated the Earth’s circumference in the 3rd century BC. He did this by comparing the angle of the Sun’s rays at Syene and Alexandria at the same moment. His estimate was remarkably close to modern measurements.

So, the question isn’t whether the Greeks knew the Earth was round. They did. The question is whether medieval Europeans forgot it. They didn’t.

Medieval Sources That Knew the Earth Was a Globe

A Middle English text predating Chaucer’s Canterbury Tales demolishes the “flat medieval world” myth outright. The Travels of Sir John Mandeville, a wildly popular 14th‑century travel narrative, explicitly describes the Earth as spherical. Mandeville discusses both the Northern and Southern Hemispheres and even explains how a traveller could, in principle, circumnavigate the globe and return from the opposite direction.

Now, Mandeville’s book is full of fanciful creatures and impossible peoples. But its popularity is the point: even a work of semi-fiction aimed at a general audience assumed a round Earth as common knowledge.

Columbus himself owned a copy. He spent money acquiring what he believed was an “authentic” version, not because he doubted the Earth’s shape, but because he hoped to find the exotic races Mandeville described. His voyage was not an attempt to prove the Earth was round, that was already settled, but to also find a shorter route to India.

So, Where Did the Flat Earth Idea Come From?

If medieval Europeans didn’t believe in a flat Earth, who did?

To find genuinely flat‑Earth cosmologies, you have to go back much further. The ancient Babylonians envisioned the world as a flat disk covered by a solid dome — the “firmament.” Elements of this cosmology appear in the Hebrew Bible and later in the Quran. These were not scientific models but theological and mythopoetic ones.

The modern flat‑Earth movement, however, is not ancient at all. It’s Victorian.

The 19th‑Century Revival: William Carpenter and His Heirs

The flat Earth was resurrected in the 19th century by William Carpenter, an English pamphleteer who wrote a series of tracts insisting that only direct sensory experience should be trusted. His argument was simple: the Earth looks flat, therefore it is flat. This empiricism-without-geometry became the movement’s central dogma.

Carpenter’s ideas nearly died with him, but his books survived — and so did the rhetorical hook: believe only what your senses can prove. It’s a seductive line, especially for people suspicious of institutions or scientific authority.

After Carpenter came a succession of enthusiasts:

• Samuel Rowbotham, whose 1849 book Zetetic Astronomy became the movement’s foundational text.
• Lady Elizabeth Blount, who helped popularise Rowbotham’s ideas and founded the Universal Zetetic Society.
• Samuel Shenton, who in 1956 created the Flat Earth Society as we know it.
• Charles K. Johnson, who led the Society through the late 20th century and turned it into a minor cultural curiosity.

The movement has always been fringe, but it has never quite died. The internet gave it a second wind.

A Final Note on Ignorance

So, the next time a politician reaches for “flat Earther” as a lazy insult, you’ll know more than the speechwriters who fed him the line. Medieval Europeans did not believe in a flat Earth. The Greeks had already proven otherwise. And the modern flat‑Earth movement is a Victorian oddity, not a medieval one.

In short: you’re now better informed than President Obama was when he delivered that applause line.

Colinxy regularly blogs at No Minister, This article was sourced HERE