A prince's military is a metaphor of his own country. Their country is considered united if it is mostly composed of his own men, yet "if one holds his states based on [auxiliaries and mercenaries], [his state is] neither firm nor safe" and is not united. Machiavelli explains that losing a situation with auxiliaries and mercenaries is the same as "one is undone, and winning, one is their captive". According to Machiavelli, a price should always be prepared for war since war is "the sole art that belongs to him who rules".
