“During the Middle Ages, scholars thought the Earth was flat.”

Discussing medieval cosmology, the entry notes that medieval thinkers inherited the classical view: "The basic structure of the cosmos was taken over from Aristotle and Ptolemy: a spherical earth at the centre of a series of concentric, rotating, transparent spheres." It explains that this geocentric model "dominated cosmological thinking in the Latin West from the thirteenth century well into the seventeenth," indicating that a spherical Earth was assumed in learned cosmological schemes.

The book description summarizes Russell’s thesis: "This book exposes the myth that Westerners in the Middle Ages believed the earth was flat. Russell shows that the spherical shape of the earth was widely known among medieval scholars and that the flat-earth legend was fabricated in the nineteenth century." It further notes that the myth was used "to support the idea that the medieval Church suppressed scientific knowledge until heroic figures like Columbus and Galileo broke free."

From late antiquity through the Middle Ages, educated Europeans accepted a broadly Aristotelian-Ptolemaic cosmology in which the Earth was a stationary sphere at the center of the universe. This geocentric model nonetheless assumed a spherical Earth, whose roundness was treated as an elementary fact in natural philosophy and astronomy.

By the early Middle Ages, educated people in Europe, following late Greek and Roman authors, took the sphericity of the Earth for granted. Medieval university instruction in astronomy, based on texts such as Sacrobosco’s *De sphaera*, opened with proofs that the Earth is a sphere.

Medieval scholars adopted a geocentric model from Aristotle and Ptolemy in which the Earth, a spherical body, stood at the center of a series of concentric celestial spheres. Works like Sacrobosco’s *Tractatus de Sphaera* (Treatise on the Sphere) were standard university texts and began by demonstrating that the Earth is round from phenomena such as the curved shadow on the Moon during eclipses and the way ships disappear hull-first over the horizon.

UD philosophy professor Kate Rogers states: "The people who lived during the Middle Ages (5th–15th centuries) didn't believe the Earth was flat." She adds: "Now, we don't know what farmer John or Hilda, the potter's wife, thought about the shape of the Earth. However, among the educated—at least later in the period, from the 9th century on—it was generally known that the Earth is round. Aristotle had said it, and there's plenty of evidence from observation."

Aristotle provided convincing proof of Earth’s roundness in the fourth century BCE, including the observations that ships disappear hull-first over the horizon and that Earth casts a round shadow on the moon during lunar eclipses. This knowledge was preserved and transmitted through the Roman Empire and into medieval times through texts and scholarly traditions. By the 13th century, the Earth’s spherical shape was regarded as established scientific fact, with influential scientists, thinkers, and clergymen such as Thomas Aquinas, Roger Bacon, Albertus Magnus, and Johannes de Sacrobosco all agreeing with this premise.

“It seems there's one fact about the Middle Ages that always seems to astound people: medieval people did not actually think the world was flat.” The article explains that educated medieval Europeans followed classical authorities such as Aristotle and Ptolemy and “accepted a spherical Earth as part of the standard cosmological model.”

Announcing a lecture on the topic, Trine University paraphrases historian Eric Goddard: "Throughout much of the 20th century and even into the 21st, the myth that medieval Europeans believed in a flat earth – disproved by the voyages of Columbus – has persisted." It adds that his presentation "will begin by demonstrating that round earth belief began with the ancient Greeks and predominated in medieval Europe" and will explore "how the myth became established in the 19th and 20th centuries."

“The idea that the uncouth people of the Middle Ages thought the Earth was flat is a myth that has been propagating since the nineteenth century.” Hannam notes that those who opposed Columbus “never claimed the world was flat, merely that it was much bigger than Columbus thought it was.” He attributes the invention and spread of the medieval flat-earth story to 19th‑century writers such as Washington Irving and Andrew Dickson White.

In the Greek-influenced world, the spherical Earth was seen as a physical fact. This understanding was the foundation of medieval cosmology throughout the Middle Ages; educated folks, theologians, monks, scientists, and university scholars nearly all accepted and taught that the Earth was a sphere. The Byzantine monk Cosmas Indicopleustes, who passionately argued for a flat, rectangular Earth, was an outlier whose work was hardly known in Western Europe and was not translated into Latin until 1706.

Cosmas Indicopleustes, a sixth‑century Byzantine monk, wrote the *Christian Topography*, in which he defended a flat, rectangular Earth modeled on the biblical tabernacle. Modern historians note that his work was idiosyncratic, was not part of the standard curriculum, and had little impact on mainstream medieval scholarship, but it does show that at least one learned author in late antiquity/early medieval Byzantium promoted a flat-Earth view.

The article states: “Columbus argued that Earth was smaller than was commonly believed. The shape of the earth wasn't in question.” It cites historian Jeffrey Burton Russell: “With extraordinary few exceptions no educated person in the history of Western Civilization from the third century B.C. onward believed that the earth was flat.”