ABSTRACT
Numerous “cosmologies,” written and unwritten, were conceived during the Middle Ages. Although their ideas were largely unrecorded, peasants and uneducated people generally must have held some views, however primitive and crude, about the structure and operation of the world. Ironically, technical astronomical treatises included relatively little on cosmology. During the thirteenth century, the problem of the eternity of the world was widely debated. Medieval natural philosophers accepted a compromise that retained both concentricity and eccentricity. The widespread assumption of a fluid heaven and orbs in the thirteenth century was yielding to an assumption of their hardness in the fourteenth century. Although the needs of technical astronomy required that the earth be removed from the center of the world by use of eccentric orbs, most natural philosophers wrote about the earth as if it lay immobile in the center of the world.
