Julius Caesar Gallic War 2.5

Caesar, having encouraged the Remi, and addressed them courteously, ordered the whole senate to assemble before him, and the children of their chief men to be brought to him as hostages; all which commands they punctually performed by the day [appointed]. He, addressing himself to Divitiacus, the Aeduan, with great earnestness, points out how much it concerns the republic and their common security, that the forces of the enemy should be divided, so that it might not be necessary to engage with so large a number at one time. [He asserts] that this might be affected if the Aedui would lead their forces into the territories of the Bellovaci, and begin to lay waste their country. With these instructions he dismissed him from his presence. After he perceived that all the forces of the Belgae, which had been collected in one place, were approaching toward him, and learned from the scouts whom he had sent out, and [also] from the Remi, that they were then not far distant, he hastened to lead his army over the Aisne , which is on the borders of the Remi, and there pitched his camp. This position fortified one side of his camp by the banks of the river, rendered the country which lay in his rear secure from the enemy, and furthermore insured that provisions might without danger be brought to him by the Remi and the rest of the states. Over that river was a bridge: there he places a guard; and on the other side of the river he leaves Q. Titurius Sabinus, his lieutenant, with six cohorts. He orders him to fortify a camp with a rampart twelve feet in height, and a trench eighteen feet in breadth.