Thucydides, History of the Peloponnesian War
Benjamin Jowett, Ed.

84. When the day dawned Nicias led forward his army, and the Syracusans and the allies again¹ assailed them on every side, hurling javelins and other missiles at them. [2] The Athenians hurried on to the river Assinarus. They hoped to gain a little relief if they forded the river, for the mass of horsemen and other troops overwhelmed and crushed them; and they were worn out by fatigue and thirst. But no sooner did they reach the water than they lost all order and rushed in; [3] every man was trying to cross first, and, the enemy pressing upon them at the same time, the passage of the river became hopeless. Being compelled to keep close together they fell one upon another, and trampled each other under foot: some at once perished, pierced by their own spears; others got entangled in the baggage and were carried down the stream. [4] The Syracusans stood upon the further bank of the river, which was steep, and hurled missiles from above on the Athenians, who were huddled together in the deep bed of the stream and for the most part were drinking greedily. [5] The Peloponnesians came down the bank and slaughtered them, falling chiefly upon those who were in the river. Whereupon the water at once became foul, but was drunk all the same, although muddy and dyed with blood, and the crowd fought for it.