The Aeneid can be divided into two halves based on the disparate subject matter of Books 1–6 (Aeneas's journey to Latium in Italy) and Books 7–12 (the war in Latium). These two halves are commonly regarded as reflecting Virgil's ambition to rival Homer by treating both the Odyssey's wandering theme and the Iliad's warfare themes. This is, however, a rough correspondence, the limitations of which should be borne in mind.
Journey to Italy (books 1–6)
Virgil begins his poem with a statement of his theme (Arma virumque cano ..., "I sing of arms and of a man ...") and an invocation to the Muse, falling some seven lines after the poem's inception (Musa, mihi causas memora ..., "O Muse, recount to me the causes ..."). He then explains the reason for the principal conflict in the story: the resentment held by the goddess Juno against the Trojan people. This is consistent with her role throughout the Homeric epics.
Flight from Troy
Also in the manner of Homer, the story proper begins in medias res (in the middle of things), with the Trojan fleet in the eastern Mediterranean, heading in the direction of Italy. The fleet, led by Aeneas, is on a voyage to find a second home. It has been foretold that in Italy, he will give rise to a race both noble and courageous, a race which will become known to all nations. Juno is wrathful, because she had not been chosen in the judgment of Paris, and because her favorite city, Carthage, will be destroyed by Aeneas's descendants. Also, Ganymede, a Trojan prince, was chosen to be the cup bearer to her husband, Jupiter—replacing Juno's daughter, Hebe. Juno proceeds to Aeolus, King of the Winds, and asks that he release the winds to stir up a storm in exchange for a bribe (Deiopea, the loveliest of all her sea nymphs, as a wife). Aeolus does not accept the bribe, but agrees to carry out Juno's orders (line 77, "My task is / To fulfill your commands"); the storm then devastates the fleet.
Neptune takes notice: although he himself is no friend of the Trojans, he is infuriated by Juno's intrusion into his domain, and stills the winds and calms the waters, after making sure that Aeolus would not try again. The fleet takes shelter on the coast of Africa. There, Aeneas's mother, Venus, in the form of a hunting woman very similar to the goddess Diana, encourages him and recounts to him the history of Carthage. Eventually, Aeneas ventures into the city, and in the temple of Juno, he seeks and gains the favor of Dido, queen of the city, which has only recently been founded by refugees from Tyre and which will later become a great imperial rival and enemy to Rome.
At a banquet given in honour of the Trojans, Aeneas sadly recounts the events that occasioned the Trojans' arrival. He begins the tale shortly after the war described in the Iliad: Cunning Ulysses devised a way for Greek warriors to gain entry into the walled city of Troy by hiding in a large wooden horse. The Greeks pretended to sail away, leaving a warrior, Sinon, to inform the Trojans that the horse was an offering and that if it were taken into the city, the Trojans would be able to conquer Greece. The Trojan priest Laocoön saw through the Greek plot and urged the horse's destruction, but his protests fell on deaf ears, so he hurled his spear at the horse. Then, in what would be seen by the Trojans as punishment from the gods, two serpents emerged from the sea and devoured Laocoön, along with his two sons. The Trojans then took the horse inside the fortified walls, and after nightfall the armed Greeks emerged from it, opening the city's gates to allow the returned Greek army to slaughter the Trojans.
In a dream, Hector, the fallen Trojan prince, advised Aeneas to flee with his family. Aeneas awoke and saw with horror what was happening to his beloved city. At first he tried to fight the enemy, but soon he lost his comrades and was left alone to fend off the Greeks. He witnessed the murder of Priam by Achilles' son Pyrrhus. His mother, Venus, appeared to him and led him back to his house. Aeneas tells of his escape with his son, Ascanius, and father, Anchises, after the occurrence of various omens (Ascanius' head catching fire without his being harmed, a clap of thunder and a shooting star). After fleeing Troy, he goes back for his wife, Creusa, but she has been killed. Her ghost tells him that his destiny is to found a new city in the West.
He tells of how, rallying the other survivors, he built a fleet of ships and made landfall at various locations in the Mediterranean: Thrace, where they find the last remains of a fellow Trojan, Polydorus; The Strophades, where they encounter the Harpy Celaeno; Crete, which they believe to be the land where they are to build their city (but they are set straight by Apollo); and Buthrotum. This last city had been built in an attempt to replicate Troy. In Buthrotum, Aeneas meets Andromache, the widow of Hector. She is still lamenting the loss of her valiant husband and beloved child. There, too, Aeneas sees and meets Helenus, one of Priam's sons, who has the gift of prophecy. Through him, Aeneas learns the destiny laid out for him: he is divinely advised to seek out the land of Italy (also known as Ausonia or Hesperia), where his descendants will not only prosper, but in time rule the entire known world. In addition, Helenus also bids him go to the Sibyl in Cumae.
Heading into the open sea, Aeneas leaves Buthrotum, rounds Italy's boot and makes his way towards Sicily (Trinacria). There, they are caught in the whirlpool of Charybdis and driven out to sea. Soon they come ashore at the land of the Cyclops. There they meet a Greek, Achaemenides, one of Ulysses' men, who has been left behind when his comrades escaped the cave of Polyphemus. They take Achaemenides on board and narrowly escape Polyphemus. Shortly after, Anchises dies peacefully of old age.
Meanwhile, Venus has her own plans. She goes to her son, Aeneas's half-brother Cupid, and tells him to imitate Ascanius. Disguised as such, Cupid goes to Dido and offers the gifts expected from a guest. With her motherly love revived in the presence of the boy, Dido's heart is pierced and she falls in love with both the boy and his father. During the banquet, Dido realizes that she has fallen madly in love with Aeneas, although she had previously sworn fidelity to the soul of her late husband, Sychaeus, who had been murdered by her brother, Pygmalion.
Juno seizes upon this opportunity to make a deal with Venus, Aeneas's mother, with the intention of distracting Aeneas from his destiny of founding a city in Italy. Aeneas is inclined to return Dido's love, and during a hunting expedition, a storm drives them into a cave in which Aeneas and Dido presumably have sex, an event that Dido takes to indicate a marriage between them. But when Jupiter sends Mercury to remind Aeneas of his duty, he has no choice but to part. Her heart broken, Dido commits suicide by stabbing herself upon a pyre with Aeneas's sword. Before dying, she predicts eternal strife between Aeneas's people and hers; "rise up from my bones, avenging spirit" (4.625, trans. Fitzgerald) is an obvious invocation to Hannibal. Looking back from the deck of his ship, Aeneas sees the smoke of Dido's funeral pyre and knows its meaning only too clearly. Nevertheless, destiny calls, and the Trojan fleet sails on to Italy.
Book 5 takes place on Sicily and centers on the funeral games that Aeneas organizes for the anniversary of his father's death. Aeneas and his men have left Carthage for Sicily, where Aeneas organizes celebratory games—a boat race, a foot race, a boxing match, and an archery contest. In all those contests, Aeneas is careful to reward winners and losers, showing his leadership qualities by not allowing for antagonism even after foul play. Each of these contests comments on past events or prefigures future events: the boxing match, for instance, is "a preview of the final encounter of Aeneas and Turnus", and the dove, the target during the archery contest, is connected to the deaths of Polites and King Priam in Book 2 and that of Camilla in Book 11. Afterward, Ascanius leads the boys in a military parade and mock battle, a tradition he will teach the Latins while building the walls of Alba Longa.
During these events (in which only men participate), Juno incites the womenfolk to burn the fleet and prevent the Trojans from ever reaching Italy, but her plan is thwarted when Ascanius and Aeneas intervene. Aeneas prays to Jupiter to quench the fires, which the god does with a torrential rainstorm. An anxious Aeneas is comforted by a vision of his father, who tells him to go to the underworld to receive a vision of his and Rome's future, which he will do in Book 6. In return for safe passage to Italy, the gods, by order of Jupiter, will receive one of Aeneas's men as a sacrifice: Palinurus, who steers Aeneas's ship by night, falls overboard.
In Book 6, Aeneas, with the guidance of the Cumaean Sibyl, descends into the underworld through an opening at Cumae; there he speaks with the spirit of his father and is offered a prophetic vision of the destiny of Rome.
War in Italy (books 7–12)
Upon returning to the land of the living, Aeneas leads the Trojans to settle in Latium, where he courts Lavinia, the daughter of King Latinus. Although Aeneas wished to avoid a war, hostilities break out. Juno is heavily involved in bringing about this war—she has persuaded the Queen of Latium to demand that Lavinia be married to Turnus, the ruler of a local people, the Rutuli. Juno continues to stir up trouble, even summoning the fury Alecto to ensure that a war takes place.
Seeing the masses of warriors that Turnus has brought against him, Aeneas seeks help from the Tuscans, enemies of the Rutuli. He meets King Evander of Arcadia, whose son Pallas agrees to lead troops against the other Italians. Meanwhile, in book 9, the Trojan camp is attacked, and a midnight raid leads to the deaths of Nisus and his companion, Euryalus. The gates, however, are defended until Aeneas returns with his Tuscan and Arcadian reinforcements.
In the battling that follows, many are slain—notably Pallas, who is killed by Turnus, and Mezentius, Turnus' close associate. The latter, who has allowed his son to be killed while he himself fled, reproaches himself and faces Aeneas in single combat—an honourable but essentially futile endeavour. In book 11, another notable, Camilla, a sort of Amazon character, fights bravely but is killed. She has been a virgin devoted to Diana and to her nation; Arruns, the man who kills her, is struck dead by Diana's sentinel, Opis.
Single combat is then proposed between Aeneas and Turnus, but Aeneas is so obviously superior that the Italians, urged on by Turnus's divine sister, Juturna, break the truce. Aeneas is injured, but returns to the battle. Turnus and Aeneas dominate the battle on opposite wings, but when Aeneas makes a daring attack at the city of Latium (causing the queen of Latium to hang herself in despair), he forces Turnus into single combat once more. Turnus's strength deserts him as he tries to hurl a rock, and he is struck in the leg by Aeneas's spear. As Turnus is begging on his knees for his life, the epic ends with Aeneas killing him in rage when he sees that Turnus is wearing the belt of his friend Pallas as a trophy.