An allusive plot of an incestuous brother-sister marriage runs through Virgil's story of Dido and Aeneas, signalled both by imagery comparing Dido and Aeneas to Diana and Apollo, moon and sun, and by allusion to Callimachean poems celebrating actual brother-sister marriages at the Ptolemaic court. Aeneas' departure from Carthage marks the relegation to the past of Alexandrian temptations and a journey to a future foundation based on exogamy, although Italy itself is not free from the dangers of incest and fratricide. Ovid's explicit tales of incest comment on Virgil's allusive narrative.