History of the Peloponnesian War

Now it was agreed on between them that when the gates were open, the Athenians should rush in, and that themselves would be easily known from the rest, to the end they might have no harm done them, for that they would besmear themselves with some ointment. And the opening of the gates would be for their greater safety, for the four thousand men of arms of Athens and six hundred horsemen, which according to the appointment were to come to them, having marched all night, were already arrived.

When they had besmeared themselves and were now about the gates, one of those who were privy discovered the conspiracy to the rest that were not. These joining their strength came all together to the gates, denying that it was fit to go out to fight, for that neither in former times when they were stronger than now, durst they do so, or to put the city into so manifest danger, and said, that if they would not be satisfied, the battle should be thereright. Yet they discovered not that they knew of the practice, but only, as having given good advice, meant to maintain it. And they stayed at the gates, insomuch as the traitors could not perform what they intended.

The Athenian commanders, knowing some cross accident had happened and that they could not take the city by assault, fell to enclosing of Nisaea with a wall, which if they could take before aid came, they thought Megara would the sooner yield. Iron was quickly brought unto them from Athens, and masons, and whatsoever else was necessary.