History of the Peloponnesian War (1.3.1-1.3.3)

There is also another circumstance that contributes not a little to my conviction of the weakness of ancient times. Before the Trojan war there is no indication of any common action in Hellas,

nor indeed of the universal prevalence of the name; on the contrary, before the time of Hellen, son of Deucalion, no such appellation existed, but the country went by the names of the different tribes, in particular of the Pelasgian. It was not till Hellen and his sons grew strong in Phthiotis, and were invited as allies into the other cities, that one by one they gradually acquired from the connection the name of Hellenes; though a long time elapsed before that name could fasten itself upon all.

The best proof of this is furnished by Homer. Born long after the Trojan war, he nowhere calls all of them by that name, nor indeed any of them except the followers of Achilles from Phthiotis, who were the original Hellenes: in his poems they are called Danaans, Argives, and Achaeans. He does not even use the term barbarian, probably because the Hellenes had not yet been marked off from the rest of the world by one distinctive appellation.