But if resentment for an offence like this so deeply moved a Roman citizen at a time when Rome was still uncorrupted, we should consider how it may act on the citizen of a State not constituted as Rome then was. And because there is no certain remedy we can apply to such disorders when they arise in republics, it follows that it is impossible to establish a republic which shall endure always; since in a thousand unforeseen ways ruin may overtake it. CHAPTER XVIII.—_That it is the highest Quality of a Captain to be able to forestall the designs of his Adversary._ It was a saying of Epaminondas the Theban that nothing was so useful and necessary for a commander as to be able to see through the intentions and designs of his adversary. And because it is hard to come at this knowledge directly, the more credit is due to him who reaches it by conjecture. Yet sometimes it is easier to fathom an enemy’s designs than to construe his actions; and not so much those actions which are done at a distance from us, as those done in our presence and under our very eyes. For instance, it has often happened that when a battle has lasted till nightfall, the winner has believed himself the loser, and the loser has believed himself the winner and that this mistake has led him who made it to follow a course hurtful to himself. It was from a mistake of this sort, that Brutus and Cassius lost the battle of Philippi. For though Brutus was victorious with his wing of the army Cassius, whose wing was beaten, believed the entire army to be defeated, and under this belief gave way to despair and slew himself. So too, in our own days, in the battle fought by Francis, king of France, with the Swiss at Santa Cecilia in Lombardy, when night fell, those of the Swiss who remained unbroken, not knowing that the rest had been routed and slain, thought they had the victory; and so believing would not retreat, but, remaining on the field, renewed the combat the following morning to their great disadvantage. Nor were they the only sufferers from their mistake, since the armies of the Pope and of Spain were also misled by it, and well-nigh brought to destruction. For on the false report of a victory they crossed the Po, and had they only advanced a little further must have been made prisoners by the victorious French.