How does the text structure help the author convey his central idea in this chapter? By describing the actions taken by the Spartans and the Romans, Machiavelli sets up a comparison with the actions of other conquering forces discussed in the chapter. By contrasting the outcomes of Spartan and Roman conquests, Machiavelli provides evidence to support his claim that a prince must destroy a free city in order to hold it. By contrasting the goals of the Spartans and the Romans, Machiavelli establishes the problem of maintaining control of a conquered city, to which he will propose a solution. By listing the effects of these Spartan and Roman conquests, Machiavelli supports his overall description of how princes do or do not maintain control over the cities they conquer.