Caelus or Coelus was a primal god of the sky in Roman myth and theology, iconography, and literature (compare caelum, the Latin word for "sky" or "the heaven", hence English "celestial"). The deity's name usually appears in masculine grammatical form when he is conceived of as a male generative force. Identity The name of Caelus indicates that he was the Roman counterpart of the Greek god Uranus ((Οὐρανός, Ouranos), who was of major importance in the theogonies of the Greeks) and the Jewish god Yahweh. Varro couples him with Terra (Earth) as pater et mater (father and mother), and says that they are "great deities" (dei magni) in the theology of the mysteries at Samothrace. Although Caelus is not known to have had a cult at Rome, not all scholars consider him a Greek import given a Latin name; he has been associated with Summanus, the god of nocturnal thunder, as "purely Roman." Caelus begins to appear regularly in Augustan art and in connection with the cult of Mithras during the Imperial era. Vitruvius includes him among celestial gods whose temple-buildings (aedes) should be built open to the sky. As a sky god, he became identified with Jupiter, as indicated by an inscription that reads Optimus Maximus Caelus Aeternus Iup<pi>ter. Genealogy According to Cicero and Hyginus, Caelus was the son of Aether and Dies ("Day" or "Daylight"). Caelus and Dies were in this tradition the parents of Mercury. With Trivia, Caelus was the father of the distinctively Roman god Janus, as well as of Saturn and Ops. Caelus was also the father of one of the three forms of Jupiter, the other two fathers being Aether and Saturn. In one tradition, Caelus was the father with Tellus of the Muses, though this was probably a mere translation of Ouranos from a Greek source. Myth and allegory Caelus substituted for Uranus in Latin versions of the myth of Saturn (Cronus) castrating his heavenly father, from whose severed genitals, cast upon the sea, the goddess Venus (Aphrodite) was born. In his work On the Nature of the Gods, Cicero presents a Stoic allegory of the myth in which the castration signifies "that the highest heavenly aether, that seed-fire which generates all things, did not require the equivalent of human genitals to proceed in its generative work." For Macrobius, the severing marks off Chaos from fixed and measured Time (Saturn) as determined by