History of the Peloponnesian War

As soon as they were come, the Syracusians again presently prepared to set upon the Athenians, both by sea and land. The Athenian generals, seeing them have another army, and their own not bettering but every day growing worse than other, but especially as being pressed to it by the sickness of the soldiers, repented now that they removed not before; and Nicias, being now no longer against it as he was but desirous only that it might not be concluded openly, gave order unto all as secretly as was possible to put forth of the harbour and to be ready when the sign should be given.

But when they were about it and everything was ready, the moon happened to be eclipsed; for it was full moon. And not only the greatest part of the Athenians called upon the generals to stay, but Nicias also (for he was addicted to superstition and observations of that kind somewhat too much) said that it should come no more into debate whether they should go or not till the three times nine days were past which the soothsayers appoint in that behalf. And the Athenians, though upon going, stayed still for this reason.