Spherical earth in medieval books and images
The spherical earth was familiar to medieval scholars. Knowledge of its shape continued beyond the end of classical antiquity rather than disappearing with it. Bede the Venerable, a Northumbrian monk who lived from about 672 to 735 AD, explained the mainstream scholarly position in On the Reckoning of Time. Mountains and plains meant the surface was not perfectly smooth, but the world as a whole was roughly a sphere. His explanation connected that shape to the visibility of stars, showing how a discussion of the heavens could also establish the form of the ground beneath observers.
The background reaches into ancient Greek thought. Early Greek views included a flat, disc-shaped world: the Iliad and Odyssey placed the Underworld beneath the ground and Tartaros beneath the Underworld. Anaximenes of Miletos and Anaxagoras of Klazomenai also described a flat earth, while Empedokles of Akragas used language meaning circular or disc-shaped. Who first proposed a spherical earth remains uncertain. Diogenes Laertios preserved conflicting claims crediting Hesiodos, Pythagoras, or Parmenides. Those claims are doubtful: surviving poetry points toward a flat world for Hesiodos, and the attribution to Pythagoras seems to rest on a poem written long after his death.
By around the end of the fifth century BC, educated people in the Greek world commonly understood the earth's sphericity. Plato explicitly described it as spherical in Phaidon. His student Aristotle developed arguments based on observable phenomena in On the Heavens. Matter drawn toward the center would form a roughly spherical earth. During a lunar eclipse, the earth casts a circular shadow on the moon, a shape consistent with a sphere regardless of the direction of illumination. Traveling north or south also changes the stars visible overhead. Those changing views indicated a curved surface, linking terrestrial shape with what an observer could see in the sky.
Bede developed the stellar argument with specific geographical examples in chapter 46 of On the Reckoning of Time. Northern stars remained visible to observers in his region, while southern stars were hidden. For observers farther south, the arrangement changed because the globe obstructed different parts of the heavens. Egypt and the neighboring country of the Troglodytes could not see the Great and Little Bear; Italy could not see Canopus. These examples gave the spherical earth a practical observational setting.
Around five hundred years after Bede, Johannes de Sacrobosco wrote Tractatus de Sphaera, an introductory astronomy textbook used for centuries after his death. Its first chapter explained a spherical earth through differences in celestial rising and setting times. Observers in the east saw these events earlier than those in the west. The same lunar eclipse could appear at different hours of the night because sunset had already occurred earlier for eastern observers. Johannes also explained that traveling south brought previously hidden stars into view and moved formerly persistent northern stars toward setting. Earth's extent, he added, made its surface appear flat to human sight.
Images and royal symbolism carried the same shape beyond astronomical explanations. A twelfth-century illustration in Hildegard of Bingen's Liber Divinorum Operum portrayed the world as a sphere, with people and trees extending radially from its surface. A fourteenth-century manuscript of L'Image du Monde, originally written by Gautier de Metz around 1246, showed another medieval depiction. The globus cruciger, a sphere topped by a cross, was a major symbol of kingship. Its globe represented the spherical earth, while the cross represented Christ's dominion over it. Exceptions existed: Lactantius rejected sphericity, and Kosmas Indikopleustes proposed a world resembling the Ark of the Covenant, with walls and a lid.
The later popular story gained influence through Washington Irving's A History of the Life and Voyages of Christopher Columbus, published in January 1828. Irving romanticized Columbus as a hero confronting people who rejected a round world. The real disagreement concerned size and distance. Scholars estimated the journey from Spain to Asia at about 15,000 miles, while Columbus estimated about 3,000 miles. Irving's book became a bestseller, was assigned to schoolchildren, and reached readers in Europe as well as North America. By 1900 it had appeared in at least 175 print editions, giving the fictional confrontation a substantial audience across generations of readers.
A familiar image attached to this popular story has its own later date. The Flammarion Engraving shows a man peering through the dome of the sky toward workings beyond it. Although often associated with medieval ideas about a flat world, it first appeared in Camille Flammarion's L'atmosphere: meteorologie populaire in 1888. Flammarion presented the scene as a fanciful imagining of an opaque sky barrier. He did not identify it as medieval or claim that medieval people believed in a flat earth.