In 1492, Christopher Columbus was shocked when his ship made landfall in a land Europeans had never explored. Along the way, he proved that Earth isn’t flat after all. Right?

Wrong: Despite a persistent legend, neither Columbus nor his Spanish patrons thought Earth was a finite plane instead of a round planet. And you can blame one of the United States’ greatest authors for creating a myth that still surrounds one of history’s best-known figures.

When Columbus set sail in 1492, he predicted he’d make landfall in Asia. Legend has it that he defied Spanish officials to do so, sailing west instead of East because he was certain the world was round.

There’s just one problem: It’s almost certain that in the 1490s, nobody thought the earth was flat. According to historian Jeffrey Burton Russell, “no educated person in the history of Western Civilization from the third century B.C. onward believed that the Earth was flat.”

That was thanks to scientists, philosophers and mathematicians who, as early as around 600 B.C., made observations that Earth was round. Using calculations based on the sun’s rise and fall, shadows and other physical properties of the planet, Greek scholars like Pythagoras and Aristotle determined that the planet is actually a sphere.

During Columbus’ time, educated people carefully studied knowledge passed down by the ancient Greeks. Thus, it’s nearly impossible—and completely implausible—that rich Spaniards of the late 15th century thought Columbus would fall off the edge of the map.

However, Columbus ran into resistance when he tried to get funding for his landmark journey for a different reason. He mistakenly believed that the circumference of Earth was very small and that by traveling west toward what he thought was China, he’d open up new trade routes. After years of negotiation and argument over the actual length of the proposed journey, he finally convinced Ferdinand II of Spain and his wife Isabella to finance the expedition.

The myth of Columbus’ supposed flat earth theory is tempting: It casts the explorer’s intrepid journey in an even more daring light. Problem is, it’s completely untrue. The legend doesn’t even date from Columbus’ own lifetime. Rather, it was invented in 1828, when Washington Irving published The Life and Voyages of Christopher Columbus.

Irving, a master storyteller, was already famous for tales like “Rip Van Winkle” and “The Legend of Sleepy Hollow” when he tackled the life of Columbus. His inspiration came after his friend, Alexander Hill Everett, the United States’ minister to Spain, invited Irving to stay with him in Madrid. While visiting the city, Irving was tempted by a giganticarchive of documents about Columbus and decided to write the explorer’s biography.

The archive may have been extensive, but Irving couldn’t help from adding fictional flourishes to Columbus’ already fascinating life. Crucially, he claimed that when the explorer told Spanish geographers the earth was not actually flat, they refused to believe him, even questioning his faith and endangering his life.

“Is there anyone so foolish, as to believe [in] people who walk with their heels upward, and their head hanging down?” one of the Catholic geographers supposedly exclaimed when Columbus told him the Earth was a circle and not a flat line.

The real fools were Irving’s readers, who were taken in by his inaccurate account. And when his book became a runaway bestseller, the supposed confrontation between the rational explorer and the dogmatic official was accepted as truth.

Over the years—and with the help of Antoine-Jean Letronne, a French author—the legend took hold. Even today, it’s a commonly held belief…even though it couldn’t be further from the truth.

Though Columbus never proved Earth was round, he did manage to upset long-held dogma in another way when he ran across a continent nobody in Europe even knew was there. (Of course, his “discovery” wasn’t new either as the Americas had been known to indigenous people for thousands of years, and Vikings since the 11th century.) He didn’t think Earth was flat, but by jumpstarting the Age of Exploration, he changed the course of human history.