The Iliad begins in medias res, which is a Latin phrase meaning “in the middle of things.” Homer made this way of starting an epic famous, and in the case of The Iliad, the poet plunges into his story nine years into the Trojan War, at the moment when a personal dispute erupts between the Achaean king, Agamemnon, and the greatest Achaean warrior, Achilles.

Because the poem begins in the middle of things like this, the inciting incident of The Iliad is different from the inciting incident of the Trojan War itself. Curiously, though, the two inciting incidents mirror each other. The event that set the Trojan War in motion occurred when Paris, the prince of Troy, stole away from Sparta with the young woman Helen. Similarly, the event that sets The Iliad in motion occurs when Agamemnon steals from Achilles a young woman named Briseis, who had come to Achilles among other spoils from victory in battle. In this way, the beginning of The Iliad symbolically repeats the beginning of the Trojan War. Yet in spite of their symbolic similarity, these two abductions have opposing effects. Whereas Paris’s abduction of Helen pushes the Achaean and Trojan armies into battle, Agamemnon’s abduction of Briseis so enrages Achilles that the warrior removes himself from battle entirely.

Although upset by the loss of a favorite prize, what bothers Achilles most is the way Agamemnon’s action upsets the norms of Greek warrior culture. Agamemnon has leveraged his power as a king to take something away from Achilles without actually earning it. Not only does this strike Achilles as a personal betrayal but it also indicates a crisis in the principles that guide warrior ethics: honor and glory. Agamemnon has not acted honorably, nor has he won glory by demonstrating bravery in battle. Even so, he walks away with the best prize simply because he’s in a position of power. What Agamemnon’s action teaches Achilles is that his own glory as a warrior is not simply a matter of personal integrity and performance; it is subject to external forces over which he has no control. Scandalized, Achilles sees no reason to continue fighting under the Agamemnon’s command. War is a matter of life and death, and if it can’t offer the kinds of rewards he’s accustomed to, then there’s no point in risking the one life he has. As Achilles puts it in Book 9: “I say no wealth is worth my life!”

The personal conflict at the heart of The Iliad has wide-ranging consequences for humans as well as gods. Upset and refusing to fight, Achilles asks his mother, the sea nymph Thetis, to intercede on his behalf with Zeus and ask the leader of the gods to turn the tide of war in the Trojans’ favor, thereby punishing Agamemnon and the Achaeans for the way Agamemnon has treated him. Zeus agrees, which immediately places him in conflict with his wife, Hera. Around the time the Trojan War began, the Trojan prince, Paris, had slighted Hera by refusing to name her the fairest of the goddesses. Being a headstrong goddess, Hera holds a grudge against Paris and all Trojans, and as a result, she hopes for an Achaean victory. The rest of the gods divide their allegiances between Zeus and Hera—and thus between the Trojans and the Achaeans.

The worlds of both humans and gods are thus split from the beginning, and for the first two-thirds of the poem, Homer describes the war as an ongoing seesaw in which the tactical advantage constantly oscillates between the armies according to the gods’ whims. Achaeans and Trojans both suffer great losses.

It isn’t until Book 16, when Achilles’s beloved friend Patroclus dies in battle, that the poem moves toward its climax. The death of Patroclus sends Achilles into paroxysms of grief, and he longs to take revenge on Hector. Achilles’s rage at Hector eclipses his rage at Agamemnon, such that Achilles finally relents on his pledge and rejoins the fight. When Achilles finally meets Hector on the battlefield, he is not content just to kill the man; after slaying Hector, Achilles straps the Trojan’s corpse to a chariot and drags it through the dirt in a grotesque spectacle of violence. Achilles then takes Hector’s body back to his camp.

Following Hector’s death, King Priam of Troy sneaks into the Achaean camp hoping to ransom his son’s body back from Achilles. Achilles sympathizes with Priam and his loss, and the two men strike a deal. The Achaeans will agree to cease fighting for as long as it takes for the Trojans to mourn and bury their beloved Hector. The poem concludes with Priam returning to a grief-stricken Troy to bury his son. 

Importantly, Homer doesn’t narrate the conclusion of the Trojan War itself. The poem ends instead on a note of grief and mourning and with the promise that the war will resume in full force the following day. As such, the ending of The Iliad powerfully echoes the theme of war’s persistence.