This article was originally published on the defunct Ancient World Magazine website and is now re-published here.
The Achilles tendon is located in the back of the lower leg, connecting the calf muscles with a point on the heel bone. It is the strongest tendon in the human body, named after Achilles, a hero of the Trojan War and one of the main characters in Homer’s Iliad.
If you’re familiar with the stories surrounding the Trojan War, you’ll no doubt know how Achilles died: he was invulnerable save for a single weak spot, his now proverbial heel, which was pierced with an arrow loosed by the Trojan prince Paris. As such, it makes sense to name the aforementioned tendon after the hero. Achilles, after all, was also the strongest of all the fighters at Troy, and also the swiftest.
But if you’ve read Homer’s Iliad, you may have noticed that Achilles is never described as invulnerable. Like all the other heroes in the epic poem, he dons armour to protect himself from harm. Indeed, when the Greek army is at a low point, Achilles’ comrade-in-arms, Patroclus, dons Achilles’ armour and leads the Myrmidons indeed battle. He then becomes the plaything of the gods, and is ultimately killed by Hector.
Something interesting happens next. Hector takes Achilles’ armour and puts it on. Immediately, Homer tells us, “Ares the dangerous war god entered him, so that the inward body was packed full of force and fighting strength” (Il. 17.210–212). Hector calls out to his companions and returned to battle, “flaming in the battle gear of great-hearted Peleion” (Il. 17.214; transl. Lattimore), i.e. Achilles, the son of Peleus.
Two points here. At first, these lines suggest that by donning the armour of a great warrior, one can be imbued with some of his strength. But there is a second point that could be made here: what if the thing that made Achilles invulnerable on the battlefield was his armour? Indeed, Homer devotes ample space in book 18 of the Iliad to how Achilles’ armour is replaced: his mother Thetis pleads with the god Hephaestus to make him a new set of armour (Il. 18.368-617).
Ancient sources on Achilles’ weak point
As far as early Greek written sources are concerned, there is no mention of Achilles having only a single weak point. The only consistent element, already mentioned by Hector in book 22 of the Iliad, is that Achilles is fated to be killed at the hands of Paris and Apollo. It’s only in the later first century BC, in the Aeneid, written by the Roman poet Virgil, that we get the first explicit mention that the god Apollo guides the arrow that Paris loosed to take down the Greek champion (Aen. 6.56-58).
Even then, it’s not clear that Achilles had a particular weakpoint. For that, we need to consult even later sources. The first to explicitly mention Achilles’ weakness is the Roman author Statius in his poem Achilleis (1.133-134). Here, it is clear that Thetis made the infant Achilles invulnerable by dipping him into the waters of the Styx, the river that separated the world of the living from the underworld.
It is also clear from the Achilleis that Thetis held her son at his ankle and therefore this remained the only spot that was vulnerable. We find similar references to Achilles’ ankle in the Bibliotheca of Pseudo-Apollodorus (E 5.3), as well as in Hyginus’ Fabulae. But if in ancient times Achilles’ weak point was ankle, how come we now talk about Achilles’ heel?
An explanation for this is provided by the Oxford English dictionary regarding the Latin word talus. This originally meant “ankle”, but changed in meaning over the course of the Middle Ages. Modern derivates, like Italian tallone and French talon, are now words that mean “heel”. As a result, when it came to identifying Achilles’ vulnerable spot, it was logical to identify it as his heel rather than his ankle (as also noted by Gantz 1993, p. 628).
Even though Homer makes no mention of it, there is one piece of evidence that provides the earliest known reference to Achilles’ vulnerable ankle. A Chalcidian pot from the now-lost Penbroke-Hope collection, dated ca. 540 BC, features a number of warriors. Clearly visible on the ground is Achilles: an arrow sticks from his back, but by far the most prominent wound is the arrow that has pierced his ankle.
The scene features a number of interesting details. The goddess Athena watches over the battle. Achilles is dead on the ground. The Lycian commander Glaucus has pierced Achilles’ ankle and pulled a rope through it to be able to drag the corpse away, but he is struck down by the Greater Ajax. Behind Glaucus we see the Trojan prince Paris: equipped with bow and quiver, he is clearly the one who loosed the fatal shot.
Some may object that it’s a bit silly for a hero to be killed by being shot in the ankle. But this is fantasy, not reality. Something similar happens in the story of the Argonauts, when Jason and his compatriots defeat the bronze giant Talos, the defender of Crete, by removing a plug in his ankle, causing his lifeforce to drain away.