Aion (Greek: Αἰών) is a Hellenistic deity associated with time, the orb or circle encompassing the universe, and the zodiac. The "time" represented by Aion is unbounded, in contrast to Chronos as empirical time divided into past, present, and future. He is thus a god of eternity, associated with mystery religions concerned with the afterlife, such as the mysteries of Cybele, Dionysus, Orpheus, and Mithras. In Latin the concept of the deity may appear as Aevum or Saeculum. He is typically in the company of an earth or mother goddess such as Tellus or Cybele, as on the Parabiago plate.
Aion is usually identified as the nude or seminude youth within a circle representing the zodiac, or eternal and cyclical time. Examples include two Roman mosaics from Sentinum (modern–day Sassoferrato) and Hippo Regius in Roman Africa, and the Parabiago plate. But because he represents time as a cycle, he may also be imagined as an old man. In the Dionysiaca, Nonnus associates Aion with the Horae and says that he: