History of the Peloponnesian War

And when the rest were over, then last of all, and with much ado, came they also down to the ditch which were in the two towers. And by this time the three hundred that were to assist the watch came and set upon them and had lights with them,

by which means the Plataeans that were on the further brink of the ditch discerned them the better from out of the dark and aimed their arrows and darts at their most disarmed parts; for standing in the dark, the lights of the enemy made the Plataeans the less discernible, insomuch as these last passed the ditch, though with difficulty and force.

For the water in it was frozen over, though not so hard as to bear, but watery, and such as when the wind is at east rather than at north. And the snow which fell that night, together with so great a wind as that was, had very much increased the water, which they waded through with scarce their heads above. But yet the greatness of the storm was the principal means of their escape.