page_title: De sphaera mundi
section_title: Spherical Earth
hierarchical_section_title: De sphaera mundi / Content / Spherical Earth
context_page_description: De sphaera mundi is a medieval introduction to the basic elements of astronomy written by Johannes de Sacrobosco c. 1230. Based heavily on Ptolemy's Almagest, and drawing additional ideas from Islamic astronomy, it was one of the most influential works of pre-Copernican astronomy in Europe.
context_section_description: Though principally about the universe, De sphaera 1230 A.D. contains a clear description of the Earth as a sphere which agrees with widespread opinion in Europe during the higher Middle Ages, in contrast to statements of some 19th- and 20th-century historians that medieval scholars thought the Earth was flat. As proof, he uses the fact that stars rise and set sooner for those in the east, and lunar eclipses happen earlier; that stars near the North Pole are visible to those further north and those in the south can see different ones;  that at sea one can see further by climbing up the mast; and that water seeks its natural shape which is round, as a drop.
caption: Picture from a 1550 edition of De sphaera
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