History of the Peloponnesian War

But the Plataeans, and only they, being Boeotians, fought against Boeotians upon just quarrel. The Rhodians and Cythereans, Doric both, by constraint bore arms; one of them, namely the Cythereans, a colony of the Lacedaemonians, with the Athenians against the Lacedaemonians that were with Gylippus;

and the other, that is to say, the Rhodians, being by descent Argives, not only against the Syracusians, who were also Doric, but against their own colony, the Geloans, which took part with the Syracusians. Then of the islanders about Peloponnesus, there went with them the Cephallenians and Zacynthians, not but that they were free states, but because they were kept in awe as islanders by the Athenians, who were masters of the sea.

And the Corcyraeans, being not only Doric but Corinthians, fought openly against both Corinthians and Syracusians, though a colony of the one and of kin to the other, which they did necessarily (to make the best of it), but indeed no less willingly, in respect of their hatred to the Corinthians. Also the Messenians, now so called, in Naupactus, were taken along to this war, and the Messenians at Pylus, then holden by the Athenians.

Moreover the Megarean outlaws, though not many, by advantage taken of their misery, were fain to fight against the Selinuntians that were Megareans likewise. But now the rest of their army was rather voluntary.