Auxiliaries are troops sent by another ruler to help you. Just as with mercenaries, if they lose, you are ruined, and if they win, you are in their power. Auxiliaries come to you as a united body trained to obey others. Mercenaries are less dangerous, because they are not united behind their leaders. A wise prince would rather lose his own troops than win with someone else's, because a victory with borrowed troops is not really a victory.
A principality that does not have its own army is not really secure, because it depends on fortune, not its own strength. Nothing is weaker than a reputation for power that is not based on your own strength.
Machiavelli views auxiliaries, troops loaned by another ruler, as even more destructive than mercenaries. While mercenaries are only self-interested, auxiliaries are actually loyal to someone else, namely a rival prince who may use them to conquer you. Using forces that belong to someone else puts you in that person's power.
Returning once again to his theme that the only real strength is self-sufficiency, Machiavelli remarks that it is better to lose with one's own troops than to win with the strength of others, because that victory belongs to them. Unless a prince can field an army of his own citizens or subjects, he has no real power. Virtù, a prince's own strength, is always preferable to relying on luck or the favor of others.
Julius Pope Julius II tried to take Ferrara, allied with the French, in 1510. Julius probably allied with Spain more out of fear of French power in Italy than out of specific desire to conquer Ferrara.
Constantinople former name for Istanbul. Christian capital of the Byzantine Empire. During a period of civil war, the emperor asked Ottoman Turkish forces to intervene. Constantinople fell to the Ottoman Empire in 1453.
David the great king of the Israelites, only a young shepherd boy when he fought for King Saul against the Philistine giant, Goliath. David's refusal of Saul's armor appears in I Samuel 17:38-40.
Charles VIII (1403-1461) King of France. His royal ordinances established permanent infantry and cavalry in the French army. His successor Louis XII reversed this policy.
Goths Germanic people who invaded and conquered most of the Roman Empire.