The poem abounds with smaller and greater allegories. Two of the debated allegorical sections pertain to the exit from the underworld and to Pallas' belt.
There are two gates of Sleep, one said to be of horn, whereby the true shades pass with ease, the other all white ivory agleam without a flaw, and yet false dreams are sent through this one by the ghost to the upper world. Anchises now, his last instructions given, took son and Sibyl and let them go by the Ivory Gate.— Book VI, lines 1211–1218, Fitzgerald trans. (emphasis added)
Aeneas' leaving the underworld through the gate of false dreams has been variously interpreted: one suggestion is that the passage simply refers to the time of day at which Aeneas returned to the world of the living; another is that it implies that all of Aeneas' actions in the remainder of the poem are somehow "false". In an extension of the latter interpretation, it has been suggested that Virgil is conveying that the history of the world since the foundation of Rome is but a lie. Other scholars claim that Virgil is establishing that the theological implications of the preceding scene (an apparent system of reincarnation) are not to be taken as literal.
The second section in question is
Then to his glance appeared the accurst swordbelt surmounting Turnus' shoulder, shining with its familiar studs—the strap Young Pallas wore when Turnus wounded him and left him dead upon the field; now Turnus bore that enemy token on his shoulder—enemy still. For when the sight came home to him, Aeneas raged at the relic of his anguish worn by this man as trophy. Blazing up and terrible in his anger, he called out: "You in your plunder, torn from one of mine, shall I be robbed of you? This wound will come from Pallas: Pallas makes this offering, and from your criminal blood exacts his due." He sank his blade in fury in Turnus' chest ...— Book XII, lines 1281–1295, Fitzgerald trans. (emphasis added)
This section has been interpreted to mean that for the entire passage of the poem, Aeneas, who symbolizes pietas (piety or morality), in a moment becomes furor (fury), thus destroying what is essentially the primary theme of the poem itself. Many have argued over these two sections. Some claim that Virgil meant to change them before he died, while others find that the location of the two passages, at the very end of the so-called Volume I (Books 1–6, the Odyssey), and Volume II (Books 7–12, the Iliad), and their short length, which contrasts with the lengthy nature of the poem, are evidence that Virgil placed them purposefully there.