For Ancient Greeks myth meant stories handed down from previous generations, father to son, story teller to story teller-at first orally then from the 8th century in writing. As to its actuality, there are historical problems with the text and no genuine evidence for Greek presence at Hisarlik, the agreed site of the city, at the time the siege, according to Homer, took place.
Did the epic arise out of the destruction of Mycenae culture around 1200 BCE, compensation to the Greeks living in the Dark ages that followed urban collapse and depopulation of the mainland?
This question involves not only the historical viability of the Trojan War but also the nature of epic genre, its concern with appearance not reality. For those of a religious disposition, it concerns the Moses story as literature genre, and other ancient stories of historical origins.