C. Julius Caesar, Gallic War

Caesar had every thing to do at one time: the standard to be displayed, which was the sign when it was necessary to run to arms; the signal to be given by the trumpet; the soldiers to be called off from the works; those who had proceeded some distance for the purpose of seeking materials for the rampart, to be summoned; the order of battle to be formed; the soldiers to be encouraged; the watchword to be given. A great part of these arrangements was prevented by the shortness of time and the sudden approach and charge of the enemy. Under these difficulties two things proved of advantage; [first] the skill and experience of the soldiers, because, having been trained by former engagements, they could suggest to themselves what ought to be done, as conveniently as receive information from others; and [secondly] that Caesar had forbidden his several lieutenants to depart from the works and their respective legions, before the camp was fortified. These, on account of the near approach and the speed of the enemy, did not then wait for any command from Caesar, but of themselves executed whatever appeared proper.