Luna (goddess) as Juno Covella, Juno of the crescent moon. Both Juno and Diana were invoked as childbirth goddesses with the epithet "Lucina". Luna is often depicted driving a two-yoke chariot called a "biga", drawn by horses or oxen. In Roman art, the charioteer Luna is regularly paired with the Sun driving a four-horse chariot ("quadriga"). Isidore of Seville explains that the "quadriga" represents the sun's course through the four seasons, while the "biga" represents the moon, "because it travels on a twin course with the sun, or because it is visible both by day and by night—for they yoke together one
Dynamics of the celestial spheres individual unmoved mover would be required to insure each individual motion in the heavens. While stipulating that the number of spheres, and thus gods, is subject to revision by astronomers, he estimated the total as 47 or 55, depending on whether one followed the model of Eudoxus or Callippus. In "On the Heavens", Aristotle presented an alternate view of eternal circular motion as moving itself, in the manner of Plato's world-soul, which lent support to three principles of celestial motion: an internal soul, an external unmoved mover, and the celestial material (aether). In his "Planetary Hypotheses", Ptolemy (c.90–168) rejected the