History of the Peloponnesian War

It appears therefore that the several Hellenic communities, comprising not only those who first acquired the name, city by city, as they came to understand each other, but also those who assumed it afterwards as the name of the whole people, were before the Trojan war prevented by their want of strength and the absence of mutual intercourse from displaying any collective action.

Indeed, they could not unite for this expedition till they had gained increased familiarity with the sea.