Machiavelli explains that all states are either republics or principalities. Among principalities, there are hereditary states, in which the prince's family have been "long established as rulers," and new principalities, which are acquired by previously unknown rulers. Some new principalities are "completely new," as was the case with Francesco Sforza, who rose from private citizen to Duke of Milan. Others are only partly new and are appended to existing states "like limbs," as was the case when the king of Spain acquired the kingdom of Naples.
Machiavelli straightforwardly sets up the subject matter of the book, beginning with the distinction between established, new, and partially new states. With his mention of Francesco Sforza, Machiavelli highlights a contemporary ruler who blurred the line between the masses and the elite, rising from citizen to prince.
Among the types of new principalities, there are those states that are accustomed to governance under a sovereign prince and those that are "used to freedom." A prince may gain his position in a new principality either with his own arms or with foreign military support. Finally, the ruler of a new principality wins his state "either by fortune or by prowess."
Machiavelli points out the importance of arms when seeking control of a new principality. Additionally, Machiavelli lays out the critical distinction between rulers who gain status through fortune or prowess.