Gallic War

Perceiving that Ariovistus kept himself in camp, Caesar, that he might not any longer be cut off from provisions, chose a convenient position for a camp beyond that place in which the Germans had encamped, at about 600 paces from them, and having drawn up his army in three lines, marched to that place. He ordered the first and second lines to be under arms; the third to fortify the camp. This place was distant from the enemy about 600 paces, as has been stated. Thither Ariovistus sent light troops, about 16,000 men in number, with all his cavalry; which forces were to intimidate our men, and hinder them in their fortification. Caesar nevertheless, as he had before arranged, ordered two lines to drive off the enemy: the third to execute the work. The camp being fortified, he left there two legions and a portion of the auxiliaries; and led back the other four legions into the larger camp.