AION. The trajectory of Aion extends for more than a thousand years over the whole of antiquity, from Homer to Nonnus of Panopolis. Its story has been recounted several times, and many controversial issues have been almost conclusively solved. In effect, taking part in the debate on the question of Aion has turned out to be something of an ordeal for scholars of ancient religions, for it requires them to conduct a painstaking investigation of Greek and Latin literature, ancient art, and religious topics of Greece, Rome, Egypt, Iran, Syria, and Mesopotamia. Moreover, tackling the topic of Aion entails coping with the basic tenets of the leading exponents of the Religionsgeschichtliche Schule (Reitzenstein, Bousset, and Norden) and testing the methodology of four of the most prominent modern historians of religions: Franz Cumont (1868–1947), Martin Persson Nilsson (1874–1967), Raffaele Pettazzoni (1883–1959), and Arthur Darby Nock (1902–1963). Before settling this matter, it is important...