In the Histories, the fourth-century historian Ephorus engages with one of the central aetia of the past: the story of how Apollo founded the oracle in Delphi (F 31b). Ephorus shifts the emphasis from the continuity of archaic time to the more dynamic time of the history of men on earth. In his discussion of the Spartan constitution and its origin (F 149), Ephorus uses aetia to give a nuanced picture of the interplay of continuity and change in human affairs. Callimachus, in the story of Acontius and Cydippe in his Aetia, juxtaposes the reference to the continuity of Acontius’ line with the eventful history of Acontius’ island of Chios, thus raising the question how stable the aetion can actually be. Rather than the aetiological formula, the beauty of the young couple, made immortal in Callimachus’ poetry, guarantees the story’s eternity. In Callimachus’ Hymn to Apollo, aetia are prominent in creating an intense moment of the sacred presence of the god, in which the present moment of the performance is just as much involved as the historical past of the city of Cyrene and the mythical past of Apollo’s deeds on earth. The aetia employed in Apollonius Rhodius’ Argonautica function as hinges between the earlier foundational deeds of the Olympian gods and the new earth-bound time-frame of the Argonauts, which is carefully measured out in terms of the days and nights the Argonauts spend at sea or on land. Overall, however, the aetia of the Argonautica emphasize continuity and eliminate further change, creating a present that is remarkably stable, while being anchored in several layers of the past