One other measure of a state's strength is whether a prince can defend himself, or whether he must rely on the help of others. If a ruler can field his own army (either his own men or paid mercenaries), he needs no outside help, but if he must hide behind his city walls, he will always need help from others. The first type has already been discussed in Chapter 6, and will be again in Chapters 12 through 14. The second type has no option but to fortify his city and lay in supplies. If he has treated his subjects well and has made preparations, others will hesitate to attack him. The free German cities follow this practice with great success. Therefore, any prince who has a strong city and has not made his people hate him is safe. Some will argue that the stresses of a siege will make the people disloyal, but a wise ruler will know how to keep up their morale, as long as there are enough weapons and supplies.
Winning the people's support is absolutely necessary if a prince faces the possibility of a siege. Sieges were commonplace in medieval and Renaissance warfare, and many medieval cities were surrounded by high walls in anticipation of just such an event. Sieges were often lengthy affairs, with the attacking army camped outside the city walls, hoping to starve out or wear down the residents inside the city's fortifications. As Machiavelli observes, a prince in this position could only wait out the siege or hope for outside help. Machiavelli considers it better for the prince to have an army he can put into the field on the offensive, so that the prince need not be dependent on the favor of others. However, a prince with a strong and loyal city is still in a good position, as long as he has made adequate preparations and keeps his people's spirits up. Finally, he gives some attention to the prince's ability to "spin" political events to his advantage; in this case, to reassure his people that the siege will be short, to remind them of the cruelty of the enemy, and to take measures to deal with anyone who is a little too outspoken in his criticism of the prince's policies.
The absolute necessity of maintaining one's own troops is a point Machiavelli revisits throughout the book, and particularly in Chapters 12 through 14, which concern how a prince should behave in military matters. Machiavelli had been active in raising a native militia to defend Florence, and he detested the common practice of hiring foreign mercenaries to fight, a practice he believed had helped to ruin Italy. Here, he praises the independence of the German cities, which had their own armies to fight for them.
German cities the Holy Roman Empire, a loose confederacy of states that comprised most of what is now Germany, as well as parts of Italy and France. In Machiavelli's time, the empire included more than 70 imperial cities, which exercised greater and lesser degrees of obedience to the Emperor, Maximilian I.