Later legends (beginning with Statius' unfinished epic Achilleid, written in the 1st century AD) state that Achilles was invulnerable in all of his body except for one heel.
lˈeɪɾɚ lˈɛdʒəndz bɪɡˈɪnɪŋ wɪð stˈæɾɪəs ʌnfˈɪnɪʃt ˈɛpɪk ɐtʃˈɪleɪd, ɹˈɪʔn̩ ɪnðə fˈɜːst sˈɛntʃɚɹi ˌeɪdˈiː stˈeɪt ðæt ɐkˈɪliːz wʌz ɪnvˈʌlnɚɹəbəl ɪn ˈɔːl ʌv hɪz bˈɑːdi ɛksˈɛpt fɔːɹ wˈʌn hˈiːl.