Early Europeans viewed the cosmos as a divinely created, spatially finite, bifurcated cosmos, divided into sublunary and superlunary realms. Objects above the lunar disc were believed to be stable, with heavenly bodies believed to be made out of a refined substance called " quintessence ". This was understood to be a crystalline, completely transparent substance that held all of the superlunary spheres in perfect order. After their creation by God, these spheres did not change except for their rotation above the Earth. Objects below the lunar sphere were subject to constant combination, separation, and recombination. This was because they consisted of the chaotic elements of earth, air, fire, and water.