Aeneas sails on weeping, and they land at Cumae, where Aeneas seeks the temple where the Sibyl speaks the oracles of Apollo. There Aeneas prays that the Trojans may now be allowed to escape the doom of Troy and promises to build temples for Apollo and Diana. The Sibyl is taken over by the god, and predicts that they have escaped the dangers of the sea only to meet worse dangers on land. A new Achilles will attack them, and Juno will continue her persecutions. The cause of war will again be a foreign bride, as Helen brought on the Trojan War. Aeneas must not give up-he will get help, and, strangely enough, from a Grecian city.
Aeneas says that he has already foreseen all these trials. What he has really come for is to find the way to the Underworld, that he may see the father he loves, whom he saved from Troy on his shoulders and who traveled with him so far. It is easy to go down into the Underworld says the Sibyl, but few have ever returned. First he must find a golden bough that is hidden in the forest; if the Fates really have ordained his descent, he will be able to pluck it. Also he has a dead friend who must be buried first. Aeneas returns to the beach and finds one of his comrades dead. While the others are burying him, Aeneas is led by his mother's doves to the golden bough, whose rich but lifeless leaves stand out against the green leaves of its tree. Aeneas breaks it and carries it to the Sibyl.
After the appropriate sacrifices, Aeneas and the Sibyl enter the dark cavern of Avernus. Virgil invokes the powers of darkness to help him retell the tale of what lies hidden deep in the earth. They come first to the region before the entrance of the kingdom of Dis (Pluto) where the shapes of all the evils that haunt humanity dwell, and the empty shadows of monsters of all kinds. Then they come to the river Acheron, where Charon ferries souls to the farther shore. Many he refuses to take, and the Sibyl explains that those he refuses have not been buried. They must stand on the bank and long in vain for a place of rest. Among them Aeneas sees Palinurus, who begs to be taken with him, but the Sibyl comforts him-his bones will be buried, and the place they are buried will be named for him. Charon at first resists taking Aeneas-other heroes have come to the Underworld to steal-but the Sibyl explains that Aeneas is different. He comes to meet his father. And he has the golden bough. Charon immediately consents.
Once across, Aeneas sees different areas where souls of differing fates dwell. In the Fields of Mourning, where those who died because of love dwell, he sees Dido, and tries once again to explain that he had to leave her. He begs her to speak to him, but she turns away, unmoved by his pleading and his pity for her. Her first husband is her comfort in this sad world, but Aeneas seems not to know that, and at first follows her, pitying and weeping for her sad fate. Then he again takes the path he has been given.
Next he reaches an area where dwell famous warriors who have fallen in battle, and he sees many Trojans, who crowd around him. The Greeks draw back in fear. The shade of Deiphobus, the son of Priam who married Helen after Paris was killed, appears, full of wounds. Aeneas asks what happened to him, and he tells how Helen betrayed him to Menelaus when Troy was sacked. Deiphobus wants to know Aeneas's story, but the Sibyl warns him that their time is running out. Calling Aeneas the glory of the Trojans, Deiphobus bids him go on and experience better fates.
Aeneas and the Sibyl come to the gates of Tartarus and see the Fury guarding it and hear the lamentations within. The Sibyl explains that here those who committed crimes and did not atone for them are punished. She names famous criminals from mythology, and also speaks of those who turned against their kin, hoarded their treasure, committed adultery, and so on. Then they come to the gates of the palace of Pluto and Persephone and lay the golden bough there, and thence to the Elysian Fields, a place of light and happiness. There the greatest and best warriors enjoy what they loved on earth, and there those rejoice who suffered for their homelands, served well as priests, were pious poets, or in other ways made human life better. Finally they come to the place where Anchises sits, contemplating the souls of those who are going to be reborn as his descendants.
Anchises welcomes Aeneas, rejoicing that his pious love for his father has overcome all obstacles. He has been so worried about him, especially in Carthage. Aeneas tries to embrace his father three times, but the shade of the father he loves slips through his arms. Aeneas then asks about the many souls who are moving toward the river Lethe in the distance, and Anchises explains that they are to be reborn, after they have drunk forgetfulness from Lethe, and that he has been longing to show Aeneas these descendants who are to be born, so that Aeneas will be as happy as Anchises is about the finding of Italy.
Aeneas is amazed that anyone could want to be born again, to live in a sluggish body again. Anchises explains that one soul animates the whole universe, and all living things are born of it. Their souls are divine fire, but their bodies keep them in darkness and full of all kinds of emotions, and even when they die, the taints of the body remain, and they must be purified. Some need only the purification, and soon attain Elysium; most will be reborn.
Anchises tells Aeneas the glory that will come to him from the famous sons who will be born from his line, showing and describing each one, now waiting for rebirth. After several early figures, he shows Romulus, who will found Rome, which will rule the earth, rejoicing in her sons. First of those Anchises calls Aeneas's Romans is Julius Caesar, then Augustus, who will bring back a golden age. He will defeat the powers of the East. How can Aeneas hesitate, when such a glorious result will come from his settling in Italy?
Then Anchises points out some earlier heroes, including an early Brutus, who condemned his own sons to die when they stirred up strife. "Unhappy! However posterity may report these deeds: / love of country will prevail and immense desire for fame" (lines 822-823). He also points out Julius Caesar and Pompey, bursting into a pathetic speech begging them not to engage in civil war. Other future Romans he points out who will conquer the cities of Greece. He is sure that other peoples will be better at creating great art, at speech making, at astronomy, but he adjures the Roman to remember that his arts are "to impose the way of peace, / to spare the conquered and to battle down the proud" (lines 852-853). Finally Anchises sees the shade of Marcellus (adopted son of Augustus, who died young), and he laments that such great gifts should have been lost, gifts that would have made Rome too powerful in the eyes of the gods.
After Anchises has kindled in his son's soul the love of coming fame, he tells him what he must do in the coming wars, and then takes the Sibyl and his son to the Gate of Ivory. Through the Gate of Horn true shades rise up to earth; through the Gate of Ivory, false dreams. Anchises sends them back to the overworld by the Gate of Ivory. Aeneas rejoins his comrades, and they sail to Caieta.
Book 6 is the central book of the epic. Here Aeneas finally has to let go of the desire for fulfillment as a human being, as he has to finally give up the hope for forgiveness of the harm he has done, when he says farewell to Dido, and he has to let go of Troy and his sorrow over her fall, as he leaves behind the mangled body of Deiphobus. And here he is shown fully and clearly the glory that waits for his descendants, so that his father's vision may become his own. No longer dependant on his father after this book, he is ready to be a true Roman hero in the books of warfare that follow. Nothing like this lengthy picture of the Underworld had, as far as we know, ever appeared in Western literature before, and it had an enormous influence on later literature, serving as one of the main inspirations for what many consider the greatest poem ever written, Dante's Divine Comedy. Dante recognized the power of this way of showing inner transformation, and he used it even more fully than Virgil had.
In Virgil, the vision of transformation is balanced always by the enormous sense of loss on the human level. Aeneas must struggle on, but it his warm human love for his father that motivates him, and that love can never really be satisfied either. As he tried three times to embrace the shade of his dead wife after the fall of Troy, so he tries to embrace his father, but the shade slips through his arms. One of the great heroes of ancient Rome, the early Brutus (NOT the Brutus who killed Julius Caesar), Virgil judges as "unhappy," and driven by love of fame as well as love of country to the horrible deed of condemning his own sons to die. Virgil tells us that Anchises fires Aeneas's soul with love of coming glory, but nothing Aeneas says makes us feel that he is so inspired. And when Aeneas wonders how anyone could ever want to be reborn into a sluggish body, we may remember that in the first words he speaks in the poem, he wishes he had died before the walls of Troy. The lament for Marcellus who died is more effective as poetry than the description of the glory of Augustus. (It is reported that Marcellus's mother fainted when she heard those words read aloud by Virgil.) And the famous lines in which Anchises gives the Romans their mission have an added poignance when we remember that this is a poet saying that art just isn't the strength of the Roman people-just and humane rule is. Anchises's adjuration to spare the defeated takes on even more poignance at the end of the poem, as the reader will see.
But what has most deeply puzzled all readers is the ending of Book 6. What is Virgil saying when he has Anchises send Aeneas and the Sibyl back to the overworld through the Gate of Ivory, the gate through which false dreams are sent? Those who put the greatest emphasis on Aeneas's having undergone a real and effective transformation in the Underworld have argued that Virgil is simply saying what time it is-true dreams were believed to come just before dawn, false dreams earlier.
Or they say that the noble Romans who were going to be reborn would of course have gone through the Gate of Horn, so Aeneas and the Sibyl had to take the other gate. Those who see Virgil as, perhaps unconsciously, against the imperialist vision Augustus expected him to glorify, see here the strongest evidence of that anti-imperialism-the dream of eternal, beneficent imperial rule by Rome, the dream Aeneas is to give his life for, is a false dream. Another interpretation suggests that Virgil is saying that Aeneas will not remember the vision he has had; he may have been changed by his time in the Underworld, but he has no superhuman knowledge to guide him in the perils to come.