Cosmas, the Tabernacle, and the Flat Earth

The Flat Earth Myth remains a compelling story despite continued efforts by historians to debunk it (I’ve discussed it before). Typically, it combines two fables: first, people in the middle ages believed that the earth was flat; second, Columbus proved that the earth was round. Washington Irving’s popular biography of Columbus, A History of the Life and Voyages of Christopher Columbus (1828) made the Columbus part of the story fashionable, while Andrew Dickson White’s History of the Warfare of Science with Theology in Christendom (1896) cemented in our collective consciousness the part about medieval people.

Occasionally we do find a person in the middle ages who argued for a flat earth. One such example is Cosmas Indicopluestes, a sixth-century Byzantine traveller-turned-monk. In his The Christian Topography he attacked pagan ideas about the sphericity of the earth and the universe. In book II, “The Christian theories regarding the form and position of the whole world, the proofs of which are taken from Divine Scripture” (and again later in book IV), he raised what he thought were various philosophical and empirical difficulties for a spherical earth resting at the center of the spherical universe, e.g.,

  • What would keep the earth steady and fixed at the center?
  • Why, if the fixed stars are all equa-distant from the earth, as they must be if the earth is at the center of the vault of the fixed stars, do the stars appear different sizes, and vary in brightness color?
  • Why do some stars seem brighter and therefore closer than some planets (he uses the example of Mars)?
  • Why do the planets progress through the zodiac at some times and move backwards at other times?
  • How can epicycles be real if the heavens are made up a perfect fifth element eternally in circular motion?

His empirical and philosophical objections are not particularly persuasive. But what makes Cosmas’s argument especially suspect to modern eyes is his unabashed reliance on scripture. He did not disguise the fact that his goal was to use scripture to refute the fictions and fables of Greeks, by which he means pagan Greek philosophers. Cosmas did not help his cause or the reputation of Byzantine scholars in general, at least in our eyes, when he argued that the earth was shaped like a parallelogram, surrounded on all four sides by oceans.

Cosmas’s model of the earth, taken from the 19th-c. edition printed by the Hakluyt Society.
Cosmas’s model of the earth, taken from the 19th-c. edition printed by the Hakluyt Society.

Cosmas placed this parallelogram inside a tabernacle, which reflected the shape of the cosmos. According to Cosmas’ reading, Moses was divinely inspired to construct the tabernacle because it mirrored the shape of the cosmos.

Cosmas’s tabernacle-shaped cosmos, taken from the 19-c. edition printed by the Hakluyt Society.
Cosmas’s tabernacle-shaped cosmos, taken from the 19-c. edition printed by the Hakluyt Society.

Cosmas became the poster child for the deluded premodern world filled with people who believed the earth was flat. Andrew Dickson White surveyed Cosmas’ ideas and ridiculed him for being deluded.

In the sixth century this development culminated in what was nothing less than a complete and detailed system of the universe, claiming to be based upon Scripture, its author being the Egyptian monk Cosmas Indicopleustes. Egypt was a great treasure-house of theologic thought to various religions of antiquity, and Cosmas appears to have urged upon the early Church this Egyptian idea of the construction of the world, just as another Egyptian ecclesiastic, Athanasius, urged upon the Church the Egyptian idea of a triune deity ruling the world. According to Cosmas, the earth is a parallelogram, flat, and surrounded by four seas. It is four hundred days’ journey long and two hundred broad. At the outer edges of these four seas arise massive walls closing in the whole structure and supporting the firmament or vault of the heavens, whose edges are cemented to the walls. These walls inclose the earth and all the heavenly bodies.…
Nothing can be more touching in its simplicity than Cosmas’s summing up of his great argument, He declares, “We say therefore with Isaiah that the heaven embracing the universe is a vault, with Job that it is joined to the earth, and with Moses that the length of the earth is greater than its breadth.” The treatise closes with rapturous assertions that not only Moses and the prophets, but also angels and apostles, agree to the truth of his doctrine, and that at the last day God will condemn all who do not accept it.

White’s criticism benefits from the clarity of hindsight and the condescension that such clarity conveys. Cosmas’ theory was an easy target. But there is no evidence that he was the vanguard of a widespread movement. Instead, he seems to have recognized that his theory was peculiar. His goal in writing his The Christian Topography was to refute the more commonly held belief that the world and the heavens were spherical. Cosmas’ ideas do not appear to have gained much traction. We don’t see any real interest in them until the end of the 17th or the beginning of the 18th century, and then again in the 19th. David Lindberg dismisses Cosmas:

Cosmas was not particularly influential in Byzantium, but he is important for us because he has been commonly used to buttress the claim that all (or most) medieval people believed they lived on a flat earth. This claim…is totally false. Cosmas is, in fact, the only medieval European known to have defended a flat earth cosmology, whereas it is safe to assume that all educated Western Europeans (and almost one hundred percent of educated Byzantines), as well as sailors and travelers, believed in the earth’s sphericity.[1]

Unfortunately, the Flat Earth Myth and Columbus’s role in it remain alluring and incredibly common. No amount of historical scholarship by itself will dislodge them from our popular consciousness. We must first understand why we hold onto these myths, why they make us feel so comfortable, what work they do for us. Only then we will have a better idea of how to replace them.

  1. David Lindberg, The Beginnings of Western Science (Chicago, ), 161.  ↩


  1. Michael Weiss says:

    When I was kid, my grandmother gave me a picture book about Columbus. (This must have been the late 50s.) I still remember the illustration showing Columbus in a shop, looking at a couple of globes and getting the idea of sailing to India. The text explained that lots of people knew the Earth was round in those days. It did say though that Columbus’s sailors feared sailing off the edge, though not until they been at sea for weeks.

    One aspect of the myth I wonder about. Of course we have plenty of evidence that literate folk knew the Earth was round, from the Greeks onward. What kind of evidence do we have for what the average medieval peasant believed? Texts of sermons? Stained-glass windows? Murals?

  2. Michael Weiss says:

    By the way, looking at the other anti-flat-earth posts you linked to, I saw the remark that “eppur si muove” myth first appeared in 1757, 125 years after Galileo’s death. Wikipedia claims that the line appears in a painting dated 1643 or 1645, thus just one to three years after Galileo’s death. Of course, that still doesn’t prove it happened.

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