According to Machiavelli, there are four main ways a prince can come into power. The first way is through prowess, meaning personal skill and ability. The second is through fortune, meaning good luck or the charity of friends. The third way is through crime, such as through a coup, conspiracy, or assassination. The fourth way is constitutional, meaning through the official support of either nobles or common people.
The most important comparison to be made is that between prowess and fortune. Obtaining a state through prowess is clearly more demanding than benefiting from simple good luck. But a prince gifted with his own prowess is possessed of a strong foundation to maintain that rule, whereas fortune is unpredictable and may lead as easily to a prince’s deposition as it had to his rise. Thus, maintaining rule is much easier when a prince has used his own skill. Because the maintenance of rule is most important to Machiavelli, he concludes that prowess is a better route to become a prince. A second comparison might be made between criminal and constitutional means of achieving power. Here, the main point of difference is not the skill and experience of the prince but popular attitudes toward the prince. A prince who comes to power through crime runs the greatest risk because he may be forced to commit some cruelty toward his subjects, endangering himself by breeding hatred and resentment among the populace. A constitutional prince, however, comes to power with the support of either the nobles or commoners, and his job consists mainly of keeping the unsupportive group satisfied with his rule.
To sum up, prowess is to be preferred over fortune because prowess leads to a more effective ruler who is likely to garner lasting glory. Constitutional princes are preferable to criminal princes not only because they are more effective, but also because a criminal prince can achieve nothing