Are Homer's masterpieces fact or fiction? the following site is to learn about the Homer's epic poems, the Illiad and Odyssey...

Clearly, Homer's two very famous epic poems cannot be
purely factual.  At least, we have no reason to believe that there once existed
creatures such as the cyclopes or Scylla.  Therefore, these are clearly not completely
factual.

But we do not know that the two epics are
completely fictional either.  For example, we do know that there was a war around a city
that is most likely the Troy that Homer talks about.  But we do not really
know that the city is Troy and we have no clue if the war
really happened the way the Iliad says it did (although the city was
destroyed).

So some parts of these epics are clearly
mythical.  As to the more realistic stuff (like the Trojan War), the link
says

Whether
or not this war really occurred, or occurred as the Greeks narrate it, is a relatively
unanswerable question.