" He also contrasts the image of the brightest star with the image of Achilles' spear: "And as a star moves among stars in the night's darkening, Hesper, who is the fairest star who stands in the sky, such was the shining from the pointed spear Achilleus was shaking…"

With this contrast, Homer conveys a sense of dramatic irony in the final battle between the two heroes.

Irony through Allusion to Past Events

The similes which in Book 22 convey irony by placing Hector in the role as the hunted, in contrast to his role as the dominant warrior throughout most of the story. Such is the case when Achilles is "…chasing him, as a dog in the mountains who has flushed from his covert a deer's fawn follows him through the folding ways and the valleys, and though the fawn crouched down under a bush and be hidden…"

These similes contain no irony within themselves, but are very ironic within the context of the larger story. Hitherto, Hector is referred to as the hunter, the premier warrior on the battlefield, with Homer portraying him "…as a flashing eagle makes his plunge upon other flying birds as these feed in a swarm by a river, whether these be geese or cranes or swans long-throated, so Hektor steered the course of his outrush straight for a vessel."

The irony is accomplished by drawing on the audience's own knowledge of Hector's own exploits in the preceding chapters.

Irony through Foreshadowing

Similar...

Homer uses similes likening Achilles to Hector's hunter in order to drive home the reality that Achilles the hunter will ultimately fall prey to his own fate. Homer describes Achilles' chase of Hector: "As when a hawk in the mountains who moves lightest of things flying makes his effortless swoop for a trembling dove, but she slips away."
Although Achilles does not meet his death in the Iliad, his death is all but assured. Because the audience knows that Achilles himself will not make it home, it makes his comparison to a proud hawk somewhat ironic.

Conclusion

The Iliad is widely recognized as the oldest and perhaps the most influential work in the history of Western literature. Its impact cannot be underestimated, as it has shaped our whole understanding of literature. Its influence is so great, in fact, that it is easy to forget that the Iliad was actually not literature at all, but a collection of orally recited poems which were often composed as they were recited. That such wit and irony can be developed so spontaneously is perhaps the most impressive feature of the Iliad.

References

Richmond Lattimore, trans., the Iliad of Homer (Chicago: University of Chicago Press, 1951).

15.381-386

IL 22.27-28

IL 22.317-319

IL 22.189-191

IL 15.689-693

IL 22.140