C. Julius Caesar, Gallic War

By Caesar's sudden arrival, it happened, as it necessarily must, to an unprovided and dispersed people, that they were surprised by our horse, while cultivating the fields without any apprehensions, before they had time to fly to their towns. For the usual sign of an enemy's invasion, which is generally intimated by the burning of their towns, was forbidden by Caesar's orders; lest if he advanced far, forage and corn should become scarce, or the enemy be warned by the fires to make their escape. Many thousands being taken, as many of the Bituriges as were able to escape the first coming of the Romans, fled to the neighboring states, relying either on private friendship, or public alliance. In vain; for Caesar, by hasty marches, anticipated them in every place, nor did he allow any state leisure to consider the safety of others, in preference to their own. By this activity, he both retained his friends in their loyalty, and by fear, obliged the wavering to accept offers of peace. Such offers being made to the Bituriges, when they perceived that through Caesar's clemency, an avenue was open to his friendship, and that the neighboring states had given hostages, without incurring any punishment, and had been received under his protection, they did the same.