My mother took me to see it when it first came out, she explained this book was like the Bible for us, it layed out the moral and religious ideas that governed our civilization.

I was pretty familiar with the Bible, all my friends went to Sunday school. But I was immediately struck by one major difference between the Judeo-Christian view of the world and the Greco-Roman one.
Adam and Eve are cast out of paradise for eating the fruit of the tree of knowledge, which had been expressly forbidden by the Lord. When Odysseus had his men tie him to the mast so he could hear the Sirens’ song, he was proclaiming the fundamental difference between the two founding documents of Western Civilization, Homer and the Old Testament. Knowledge is worth any price, even the risk of death and damnation.

https://www.youtube.com/watch?v=CEJUWsHLTeI

Homer is a voice from the end of the Bronze Age. The Trojan War he describes is an event that occurred at the end of the Mycenaean age. Shortly after, a great catastrophe swept across the ancient world, causing a number of empires and civilizations to collapse, including Mycenae itself. No one is quite sure what caused this collapse, it might have been the volcanic eruption and tsunami that destroyed Thera and many of the coastal states of the eastern Mediterranean. Or it might have been the loss of the tin mines in Asia (needed to make bronze) due to barbarian invasion. But for one reason or another civilization in the eastern Med collapsed, the period is known as the Greek Dark Ages (1100-800 BCE). There was the usual result, mass migrations, widespread war and conflict, the end of urban life and trade, and the loss of literacy. The Minoans and Myceneans had writing, but it was lost and the eastern Med had no alphabet until Greece adopted a variant of Phoenician script during the Archaic period (800-480 BCE).

Historians believe stories of endless conflict between the Myceneans and the peoples of Asia Minor survived as the tale of the Trojan War, but these were all preserved as part of an oral tradition, long songs memorized by bards and sung around campfires and in smoky halls for almost a thousand years. After the introduction of writing in the Archaic period, these old stories were written down and condensed, compared, combined and edited into more or less the versions we are familiar with today. We know how this process works because it happens over and over again (the Icelandic Sagas, the Hindu Vedas, the Old Testament).

By the time of the Classic period of Greek history (480-323 BCE), the time we study in school, the time of the Parthenon, Aristotle, Plato and Socrates and the Peloponnesian War, the “definitive” version was written down on papyrus. This is the Homer the Greeks, then the Romans, and finally the modern age were taught. Much of the art and literature of Classical Greece, as well as the later Romans and even the moderns reflects this Iliad and Odyssey, and was often portrayed in the art of the time or discussed in its literature. The iconography pottery and sculpture of antiquity is often based on Homeric themes, so we are used to seeing pictures of Homeric heroes and gods dressed in clothes and armor appropriate to the times when the art was produced, not the time of the events in the text. For example, Odysseus’ ships did not look like this:

https://upload.wikimedia.org/wikipedia/commons/thumb/d/df/Exekias_Dionysos_Staatliche_Antikensammlungen_2044.jpg/500px-Exekias_Dionysos_Staatliche_Antikensammlungen_2044.jpg

And he did not wear armor like this:

https://upload.wikimedia.org/wikipedia/commons/thumb/6/66/Fight_Andokides_Louvre_G1.jpg/500px-Fight_Andokides_Louvre_G1.jpg

Every age is likely to make errors like this, medieval depictions of Classical scenes often show clothing and armor appropriate to their own time, not the poorly remembered dim past.

So if you catch Matt Damon in a crested broom helmet, or sailing in something that looks like a Viking long ship, its no big deal. We’re not the only age to get the details wrong.