[Renfield]

We don't even know that those heroes were "Greek". Homer calls them the Achaeans, meaning something like "allies".

There is abundant evidence to indicate that Troy, and the Trojan war, didn't happen in the Mediterranean at all, but in northern Europe, perhaps as a struggle of early Celts; and that Homer was merely reciting his version of an older conflict, the news of which has passed widely throughout ancient Europe. I suggest a reading of the book Where Troy Once Stood, by Iman Jacob Wilkens, for a good exposition of an alternate interpretation of the particulars of that conflict.

[Verginius Rufus]

Homer has three terms for the Greeks--Achaeans, Argives, and Danaans. The term Hellene became widespread much later. Our word Greek comes from the Roman label for them, Graeci. The Hittite archives have references to "Ahhijawa" who are thought to be "Achaeans."

Whether there really was a Trojan War is disputed. Maybe something similar happened in Celtic Europe (not unlikely given they were all a bunch of bloodthristy Indo-European tribes), but the Greeks would have known nothing of anything in northern Europe. It's possible there was an older story about a siege that happened to be applied to the ruins at Troy after Greeks settled in the area.