What are the differences between principalities and republics, and why are they the only types of government he thinks exist?

[Ann]

In Chapter 1, Machiavelli states that the important difference between a principality and a republic is the structure of their leadership. A principality is ruled solely by one person, the prince, who possesses all authority to make and enforce policy. In contrast, in a republic, governing authority is distributed among representatives from the various classes of a city. Machiavelli states that anarchy is not a form of government but a lack of government. Thus, the tension between the interests of the two classes is resolved by either giving all authority over to a single person (a principality) or by distributing authority over many people (a republic or free city).