The Greek hero Achilles had one famous physical weakness: his heel. According to myth, his entire body was invulnerable except for that single spot, which is where a poisoned arrow ultimately killed him during the Trojan War. But Achilles also carried deeper, less literal weaknesses. His pride and uncontrollable rage shaped his fate just as much as that unprotected heel.
How His Heel Became His Only Weak Spot
Achilles was the son of Thetis, a sea goddess, and Peleus, a mortal king. Because he was half-mortal, Thetis wanted to protect her son from death. Shortly after his birth, she dipped him into the River Styx, the boundary river of the underworld, whose waters could make flesh impervious to weapons. But she held the infant by his heels as she submerged him, and the water never touched that spot. His heels remained ordinary, unprotected human flesh.
This origin story is actually a later addition to the myth. Homer’s original “Iliad,” written around the 8th century BCE, never mentions the River Styx dipping or a vulnerable heel. The specific details about Thetis and the river come from the Roman poet Statius, who wrote “The Achilleid” around the 1st century CE, more than 700 years after Homer. Statius is the one who gave the myth its most recognizable shape: the desperate mother, the magical river, and the fatal oversight of an uncovered heel.
How Achilles Died
Achilles was the greatest warrior on the Greek side during the siege of Troy, virtually unstoppable on the battlefield. His most famous victory was killing Hector, Troy’s champion. But his death came not from a worthy opponent in direct combat. It came from Paris, a Trojan prince better known for starting the war by stealing Helen than for his skill as a fighter.
In the most widely told version, Paris shot Achilles with an arrow that was guided by Apollo, the god who favored the Trojans. The arrow struck Achilles in his heel, the one spot where he could be harmed, and killed him. Some versions say the arrow was poisoned. There is also an alternate telling in which Achilles fell in love with the Trojan princess Polyxena and negotiated a marriage with King Priam. During the private ceremony, Paris hid in the bushes and shot Achilles with a divine arrow, seeing the marriage as a threat since it would have ended the war and forced him to return Helen.
Either way, the greatest warrior of the Greek world was brought down not by a superior fighter but by a single arrow to an overlooked vulnerability. That irony is the core of the story’s lasting power.
His Pride and Rage as Deeper Flaws
The heel gets all the attention, but in Homer’s telling of the Trojan War, Achilles’ real weakness is his character. The entire plot of the “Iliad” is driven not by a physical wound but by Achilles’ pride and fury. The poem’s famous opening line announces its subject: the rage of Achilles.
The conflict begins when Agamemnon, the Greek commander, takes a war prize (a captive woman named Briseis) from Achilles as a show of authority. Achilles considers this a devastating insult to his honor. His response is not measured. He withdraws entirely from the war, refusing to fight while his fellow Greeks are slaughtered on the battlefield. He even asks his mother Thetis to persuade Zeus to let the Trojans win for a while, just so the Greeks will realize how badly they need him. Thousands of soldiers die because of his wounded pride.
Achilles only returns to battle after his closest companion, Patroclus, is killed by Hector while wearing Achilles’ own armor. His grief transforms into a rage so extreme that after killing Hector, he drags the body behind his chariot for days, refusing to let the Trojans bury their prince. This behavior horrifies even the gods.
Literary scholars describe this pattern as hubris, an excessive pride and overconfidence that blinds a hero to the consequences of his actions. Achilles’ godlike abilities feed his sense of superiority, which in turn makes him prone to intense passion and recklessness. He is not simply angry. His anger is, as one analysis puts it, “unparalleled in its intensity,” a force that harms his allies nearly as much as his enemies.
Why “Achilles’ Heel” Became a Universal Phrase
The image of an otherwise invincible person undone by one small vulnerability was too useful to stay inside mythology. “Achilles’ heel” entered everyday language as a phrase meaning any critical weakness in something that otherwise appears strong. You hear it in sports, business, politics, and personal conversation.
The myth also left a permanent mark on medicine. The thick tendon running from the calf muscle to the heel bone is called the Achilles tendon, named after the hero’s fatal weak point. It is the strongest tendon in the human body, yet it is also one of the most commonly injured, a fitting echo of the original story: strength and vulnerability in the same spot.