Homer wrote the Odyssey and the Iliad between 750 and 650 BC. Around 570 BC, Xenophanes introduced the notion that the Greek gods were false. Instead, the real god was without body:

Clement of Alexandria Miscellanies 5. 109: Xenophanes of Colophon puts it well indeed in teaching that god is one and without a body (asomatos): “There is one god, greatest among gods and men, who is not like human beings either in form (demas) or in thought (noema).”

Xenophanes began to criticize the Greek gods:

Sextus Empiricus, Adversus Mathematicos 9. 193: “Xenophanes, refuting Homer and Hesiod and their followers, says: ‘Homer and Hesiod have ascribed to the gods everything which is shame (oneidea) and blame (psogos) for human beings: stealing, committing adultery, and deceiving one another.'”

This notion became popular by the time of Plato. Plato openly writes that he would abolish the Greek myths in his ideal state:

But the narrative of Hephaestus binding Here his mother, or how on another occasion Zeus sent him flying for taking her part when she was being beaten, and all the battles of the gods in Homer –these tales must not be admitted into our State, whether they are supposed to have an allegorical meaning or not. For a young person cannot judge what is allegorical and what is literal; anything that he receives into his mind at that age is likely to become indelible and unalterable; and therefore it is most important that the tales which the young first hear should be models of virtuous thoughts.

In Plato we see the beginnings of a new trend. Homer’s stories are becoming allegorized. In order to salvage Homer, the Greeks had started saying that Homer did not actually mean these stories to be true. Instead, the stories teach principles. It was even claimed that Homer did not believe the stories to be true, but instead believed in a Platonic principle of god:

And the poet Homer, using the license of poetry, and rivalling the original opinion of Orpheus regarding the plurality of the gods, mentions, indeed, several gods in a mythical style, lest he should seem to sing in a different strain from the poem of Orpheus

This is from Justin Martyr’s Address to the Greeks. Justin later states:

In this passage Homer seems to me without doubt to have learnt in Egypt, like Plato, concerning the one God, and plainly and openly to declare this, that he who trusts in the really existent God makes no account of those that do not exist. For thus the poet, in another passage, and employing another but equivalent word, to wit, a pronoun, made use of the same participle employed by Plato to designate the really existent God, concerning whom Plato said, “What that is which always exists, and has no birth.”

Although Justin is a self-proclaimed Christian he is not appealing to anything new in Greek culture. The Greeks had long taken Homer as allegorical, ascribing very Platonic ideas about god to Homer. Homer’s status can best be compared to the Bible. Although many modern Christians do not believe that many events described in the Bible actually happened (such as Moses convincing God to repent in Exodus 32), they see themselves as true to the Bible. They allegorize and reinterpret the events to fit their theology, no matter how poorly it fits the Bible. The Greeks did this too. Here is Plutarch:

Let us begin with the beginning and creation of the whole universe, which Thales the Milesian refers to the substance water, and let us see whether Homer first discovered this when he said (I. xiv. 246):—

Even to the stream of old Oceanus Prime origin of all.

After him Xenophanes of Colophon, laying down that the first elements were water and land, seems to have taken this conception from the Homeric poems (I. vii. 99):—

To dust and water turn all ye who here inglorious sit.

For he indicates their dissolution into the original elements of the universe. But the most likely opinion makes four elements,— fire, air, water, earth. These Homer shows he knows, as in many places he makes mention of them.

Plutarch drew from Homer, although it was not present, the Greek understanding of elemental creation of the Earth. Reading Plutarch’s work, the entire narrative is filled with such examples. In fact, Plutarch attributes to Homer the understanding of all science:

Homer, who was in time first among most poets and by his power first of all poets, we justly read first, thereby gaining the greatest advantages for our language, for our intellect, and for practical knowledge.

…

And indeed in these fabulous narratives, if one reads not unattentively but carefully each element of what is said, Homer appears to have been at home in the whole sphere and art of logic, and to have supplied many incentives, and as it were seeds of all kinds of thought and action to his posterity, not to poets alone, but to the authors of historical and scientific works.

To Homer, Plutarch describes the same general thoughts outlined by Justin Martyr. Everyone reinterpreted Homer into myth. Their claim became one echoed by modern Christians about the Bible: Homer really believed in Platonic god/gods and had to dumb down his writing for the audience:

But poetry requires gods who are active; that he may bring the notion of them to the intelligence of his readers he gives bodies to the gods. But there is no other form of bodies than man’s capable of understanding and reason. Therefore he gives the likeness of each one of the gods the greatest beauty and adornment. He has shown also that images and statues of the gods must be fashioned accurately after the pattern of a man to furnish the suggestion to those less intelligent, that the gods exist.

The lesson Christians should learn is that it is all too easy to dishonestly supplant the words of a text with wrong understandings in order to salvage theology. The case of Homer should serve as an illustration and a warning.