Chapter 13 — Auxiliaries, Mixed Soldiery, and One's Own

The distinction between mercenaries and auxiliaries matters because they fail in different ways. Mercenaries are problematic because of their internal divisions and their lack of commitment; they can sometimes be managed by a sufficiently shrewd employer. Auxiliaries are problematic because they have none of these weaknesses — they are well-organised, disciplined, and loyal. The problem is that their loyalty is owed entirely to the foreign prince who sent them. A victorious auxiliary army is a foreign army in your territory; a defeated one leaves you exposed to the enemies they failed to repel.

Julius II's military adventures provide the contemporary example. Having found his own mercenaries unreliable in the Ferrara campaign, he contracted with Ferdinand of Spain for auxiliary troops — throwing himself, as Machiavelli notes with characteristic dryness, entirely into the hands of a foreigner. Julius was fortunate enough to have his Spanish auxiliaries succeed and withdraw, but his luck was the exception. The Florentines used ten thousand French troops to take Pisa and found themselves more endangered by their own army than by the enemy. The Byzantines invited ten thousand Turkish troops into Greece to settle a quarrel with their neighbours; when the war ended, the Turks refused to leave, and Greek servitude to the Ottomans began.

Cesare Borgia's career traces the opposite trajectory — from dependence to independence — and Machiavelli presents it as the model. Borgia began with French auxiliaries, moved to the Orsini and Vitelli mercenaries when he found the French unreliable, and then, when the mercenaries proved treacherous in turn, built his own army from the territories he controlled. By the end he had an army that was entirely his own, loyal and capable. Machiavelli's maxim closes the chapter: a prince's own arms alone are truly his own; all other kinds are either useless or dangerous.