All this was known to Cæsar. He was acquainted with their plans, their positions, with what met the eye, and what was hidden, and he prepared to turn the enemy's stratagems to their own destruction. To Seius Tubero, his chief officer, he assigned the cavalry and the plain. His infantry he drew up so that part might advance on level ground into the forest, and part clamber up the earthwork which confronted them. He charged himself with what was the specially difficult operation, leaving the rest to his officers. Those who had the level ground easily forced a passage. Those who had to assault the earthwork encountered heavy blows from above as if they were scaling a wall. The general saw how unequal this close fighting was, and having withdrawn his legions to a little distance, ordered the slingers and artillerymen to discharge a volley of missiles and scatter the enemy. Spears were hurled from the engines, and the more conspicuous were the defenders of the position, the more the wounds with which they were driven from it. Cæsar with some prætorian cohorts was the first, after the storming of the ramparts, to dash into the woods. There they fought at close quarters. A morass was in the enemy's rear, and the Romans were hemmed in by the river or by the hills. Both were in a desperate plight from their position; valour was their only hope, victory their only safety.