 From the middle Imperial period, the title "Caelestis", "Heavenly" or "Celestial" is attached to several goddesses embodying aspects of a single, supreme Heavenly Goddess.The "Dea Caelestis" was identified with the constellation Virgo ("The Virgin"), who holds the divine balance of justice.In the "Metamorphoses" of Apuleius, the protagonist Lucius prays to the Hellenistic Egyptian goddess Isis as "Regina Caeli", "Queen of Heaven", who is said to manifest also as Ceres, "the original nurturing parent"; Heavenly Venus "(Venus Caelestis)"; the "sister of Phoebus", that is, Diana or Artemis as she is worshipped at Ephesus; or Proserpina as the triple goddess of the underworld.