When Columbus set sail in 1492, he proved - for the first time - that Earth was round. Europeans laughed at Columbus, certain he would fall off the edge of the flat Earth. If you've heard that story, you aren't alone. There's just one problem: It's completely false. Dating back to the 6th century, educated Greeks, Romans, and medieval Europeans knew Earth was a sphere. Medieval Christian writers explained Earth was like a ball, and scientists even calculated Earth's circumference with remarkable accuracy.
Long before Columbus, Europeans made globes, which would be pretty strange if they thought Earth was flat. And educated people weren't the only ones who knew Earth was round. Even illiterate sailors didn't believe Earth was flat for a simple reason.
In fact, bizarre flat-Earther theories are much newer than the 15th century. Most of them come from a 19th-century hoax invented by the same guy who came up with the Headless Horseman. But proof that medieval people knew Earth was round probably won't sway flat-Earthers who've attempted to justify a patently silly theory.
Ancient Greeks as far back as the 6th century BCE knew Earth was round. Pythagoras, Aristotle, and Euclid all wrote that Earth was a sphere. The Romans recognized Earth's shape, too. In the 2nd century CE, Ptolemy wrote Geography, which became the most important text on geography for over a thousand years. To Ptolemy and his readers, Earth's shape was simply a fact.
Multiple medieval scholars wrote that Earth was a sphere, including Sacrobosco's book, aptly called De Sphaera Mundi or "the sphere of the world." Among medieval thinkers, there was simply no debate about Earth's shape: It was a sphere.
For centuries, scientists and mathematicians knew Earth was round. They conducted experiments based on the length of shadows, the rise and fall of the sun, and the vanishing point of ships. By 1492, during the height of the Renaissance and its rebirth of Greek science, educated people knew Earth was round. Columbus never set out to disprove a flat Earth. In fact, he was more interested in money than making a scientific point.
If Columbus wasn't challenging European knowledge, why did so many rulers refuse to support his journey? Columbus was seriously wrong about one thing. He significantly miscalculated the circumference of Earth, estimating that he could reach China by sailing for just four weeks. Rulers who knew ancient Greek calculations on the circumference doubted Columbus's calculations. And they were right: It took Columbus five weeks to reach the New World.
Did medieval Europeans think the world was flat? A famous 15th-century globe disproves that myth. In 1492, the same year Columbus set sail, a German geographer named Martin Behaim created a globe representing Earth. Called the Erdapfel, or "Earth apple," and commissioned by the city of Nuremberg, Behaim's globe showed the world before Columbus's expedition. The globe included Europe, Asia, and Africa surrounded by water.
Critically, Behaim wasn't the first to create a globe. The first-known globe dates back to the 2nd century BCE, when Greek philosopher Crates of Mallus made a globe. A century later, Strabo described the now-lost ancient globe as having a "spherical surface."
In the 2nd century CE, Ptolemy wrote Geography, which was built on Greek science demonstrating Earth was round. In fact, the biggest problem Ptolemy tackled in his book was how to portray a round Earth on flat paper. Ptolemy popularized the idea of latitude and longitude as a method to locate points on Earth's round surface. And he used the system to create mathematically based projections for creating world maps.
Ptolemy's work remained popular for centuries, through the Age of Exploration, and maps based on his projections showed Earth's curve visually. Ptolemy's world map stayed popular into the 16th century, suggesting medieval Europeans knew Earth was round.