Nicole Oresme was a French philosopher, mathematician, and theologian (he served as bishop of Lisieux) who reformulated Aristotle's doctrine of natural place in a way that allowed for the possibility of other worlds. Oresme taught that the doctrine was valid providing only that heavy bodies were located more centrally than light ones. Since there could be many centers, there could, in principle, be many different systems of worlds. However, almost all medieval scholastics stressed that God in fact had created only one world.