Final answer:
In Cumae, Aeneas seeks the guidance of the Sibyl to navigate the underworld and learn about the future of his descendants.
Step-by-step explanation:
Aeneas looks for the Sibyl in Cumae. The Sibyl serves as his 'travel guide' during his journey through the underworld. It is part of his quest to learn about the future and the fates of his descendants, which leads him to encounter various souls and learn from his father Anchises about the Stoic cosmology and the destiny of the Roman people.
This narrative is an essential part of the epic poem, The Aeneid, written by the Roman poet Virgil, which intertwines elements from Hellenistic, Jewish, Greek, and Roman cultural motifs.