Plataicus (26-30)

But one thing the Thebans will not be able to say—that they remain loyal to their associates, though there is reason to fear that we, having recovered our country, will desert to the Lacedaemonians; for you will find, Athenians, that we have twice been besieged[*] and forced to surrender because of our friendship for you, while the Thebans often have wronged this city.

It would be a laborious task to recount their treacheries in the past, but when the Corinthian war broke out because of their overbearing conduct and the Lacedaemonians had marched against them, although the Thebans had been saved by you, they were so far from showing their gratitude for this service that, when you had put an end to the war, they abandoned you and entered into the alliance with the Lacedaemonians.

The people of Chios, of Mytilen, and of Byzantium remained loyal, but the Thebans, although they dwelt in a city of such importance, did not have the fortitude even to remain neutral, but were guilty of such cowardice and baseness as to give their solemn oath to join the Lacedaemonians in attacking you, the saviors of their city. For this they were punished by the gods, and, after the Cadmea was captured, they were forced to take refuge here in Athens. By this they furnished the crowning proof of their perfidy;

for when they had again been saved by your power and were restored to their city, they did not remain faithful for a single instant, but immediately sent ambassadors to Lacedaemon, showing themselves ready to be slaves and to alter in no respect their former agreements with Sparta. Why need I speak at greater length? For if the Lacedaemonians had not ordered them to take back their exiles and exclude the murderers, nothing would have hindered them from taking the field as allies of those who had injured them, against you their benefactors.

And these Thebans, who have recently behaved in such fashion toward your city and in times past have been guilty of betraying Greece as a whole,[*] have seen fit to demand for themselves forgiveness for their evil deeds willingly committed and so monstrous, yet to us, for acts done under compulsion, they think no mercy ought to be shown, but they, true Thebans as they are, have the effrontery to reproach others for siding with the Lacedaemonians, when they, as we all know, have for the longest time been in servitude to them and have fought more zealously for Spartan domination than for their own security!