“People used to believe the Earth was flat.”

The notion that people once widely believed the Earth was flat is a pervasive historical misconception. This enduring myth largely gained traction in the 19th century, notably popularized by American author Washington Irving. In his 1828 biography of Christopher Columbus, Irving dramatized a fictional confrontation where Columbus argued for a spherical Earth against ignorant churchmen who insisted it was flat. This narrative was further cemented by historians like John William Draper and Andrew Dickson White, who used it to illustrate a supposed conflict between scientific progress and religious dogma, particularly in the context of debates surrounding biological evolution.

However, historical and scientific evidence overwhelmingly refutes this idea. The concept of a spherical Earth emerged in ancient Greek philosophy with Pythagoras around 500 BCE, and by the time of Aristotle in the 4th century BCE, strong empirical evidence supported this view. This understanding was widespread among educated individuals in the Greek world and continued to be accepted by scholars throughout the Roman Empire and the Middle Ages. In fact, most medieval scholars not only acknowledged the Earth's sphericity but also had a good estimate of its circumference. Columbus's challenge was not convincing others the Earth was round, but rather his underestimation of its size and the vastness of the ocean between Europe and Asia.

Despite the historical accuracy, the flat-Earth myth persists in popular culture and some educational materials. This is partly because it offers a compelling, albeit incorrect, story of brave explorers and scientific reason triumphing over perceived medieval ignorance. It fits into a broader narrative of an "eternal war between science (good) and religion (bad)," which has been perpetuated in various forms. While ancient civilizations did subscribe to flat-Earth cosmographies, the idea of a spherical Earth was well-established among educated people for centuries before Columbus's voyage, making the widespread belief in a flat Earth during the Middle Ages a convenient, yet inaccurate, historical fable.