When Roman artists needed to show that a scene took place beneath the whole vault of heaven, they reached for a recognizable figure: a mature, often bearded man, sometimes nearly nude, holding a great arc of billowing drapery over his head like a canopy, a gesture called velificatio, sky-veiling, that ancient viewers read instantly as the sky itself in personified form. This image appears on state reliefs and on carved gems of the imperial court, most famously hovering above the enthroned figure of Augustus on the Gemma Augustea, where Caelus's overarching canopy signals that the emperor's rule extends, symbolically, under the whole of heaven. The same billowing gesture recurs on sarcophagi and in cosmological scenes throughout the imperial period, sometimes paired with a personified Earth or Ocean below to frame the entire created order in a single composition.
Caelus also appears, more esoterically, in the visual program of the Mithraic mysteries, where a reclining or arching sky figure sometimes frames the central tauroctony alongside a zodiac band, situating Mithras's act within the fixed order of the heavens. Unlike Jupiter or Sol, Caelus received no processions, no priesthood and no feast day; his religious life, so far as the evidence shows, was iconographic and philosophical rather than cultic, a figure invoked by sculptors, poets and cosmologists to gesture at totality rather than a god petitioned for favor.