C. Julius Caesar, Gallic War

The soldiers of the ninth and tenth legions, as they had been stationed on the left part of the army, casting their weapons, speedily drove the Atrebates (for that division had been opposed to them,) who were breathless with running and fatigue, and worn out with wounds, from the higher ground into the river; and following them as they were endeavoring to pass it, slew with their swords a great part of them while impeded (therein). They themselves did not hesitate to pass the river; and having advanced to a disadvantageous place, when the battle was renewed, they [nevertheless] again put to flight the enemy, who had returned and were opposing them. In like manner, in another quarter two different legions, the eleventh and the eighth, having routed the Veromandui, with whom they had engaged, were fighting from the higher ground upon the very banks of the river. But, almost the whole camp on the front and on the left side being then exposed, since the twelfth legion was posted in the right wing, and the seventh at no great distance from it, all the Nervii, in a very close body, with Boduognatus, who held the chief command, as their leader, hastened toward that place; and part of them began to surround the legions on their unprotected flank, part to make for the highest point of the encampment.