History of the Peloponnesian War
Thucydides
Thucydides. History of the Peloponnesian War. Crawley, Richard, translator. London and Toronto: J. M. Dent and Sons Ltd.; New York: E. P. Dutton and Co., 1914.
While such was the fate of the party in Plataea,
the rest of the Thebans who were to have joined them with all their forces before daybreak, in case of anything miscarrying with the body that had entered, received the news of the affair on the road, and pressed forward to their succor.
Now Plataea is nearly eight miles from Thebes, and their march was delayed by the rain that had fallen in the night, for the river Asopus had risen and was not easy of passage;