Homer isn't a good source for just about anything. Homer wasn't a guy, and even if he was a guy the what we have in the Homeric epics developed over a process of somewhere between 700 and 1000 years.

To start, oral poetry isn't memorized; it's improvised or recomposed each time a particular poem is performed. The poet knows the broad strokes of the plot, he knows which stories his listeners expect to hear, but the details change as the poet spontaneously generates the poetry according to meter using a series of set phrases like "swift-footed Achilles." Phrases like this have a known metrical value which can be used to fill specific gaps in a line. Milman Parry proved this in the 30s. If you like a comparative example, there is an archive of Turkish Oral Narrative that even if you don't speak the language can give you an idea of how this works.

Ok, so how do we go from oral poetry originating sometime around 1200 BCE to the set text you read if you take a class in ancient Greek? There are two possibilities. Peisistratos, the tyrant of Athens in the 500s, instituted as part of the Dionysia contests in reciting Homer. If you're judging different poets, you need a standard to judge them against, and Peisistratos had produced maybe for the first time a written version of Homer's epics (and maybe made changes like inserting Athens into the Catalog of the Ships), so the oral performance became locked in text. That might be the basis of the text we read today.

The other possibility is it was produced by scholars in Alexandria, who were engaged in an early form of text crit; striking out line they didn't like and such.

So, if you're looking for history about the dark ages, you have a text that wasn't authored by Homer, wasn't written down by Homer, and was subject to manipulations hundreds of years after he lived, if he existed.