Write a list of the princes/people Machiavelli mentions in Chapter 20 of The Prince and indicate the reference he makes to each.
Machiavelli mentions many people for many reasons throughout The Prince. Some that he mentions in Chapter 20 ("Are Fortresses, And Many Other Things To Which Princes Often Resort, Advantageous Or Hurtful?") are of interest. Early in the chapter, Machiavelli mentions the Guelph and Ghibelline political factions that are active in unnamed tributary cities of Venice that keep the citizens distracted from uniting against their overlords, the Venetians. Of course Guelph and Ghibelline are the names of the leaders of the two factions.
Later he discusses the political strategy of destroying fortresses as a strategic move in making the principality more defensible. He cites Nicolo Vitelli as having destroyed "two fortresses in Citta di Castello" in just such a strategic move. An interesting situation Machiavelli mentions is the case of Countess Forli who was attacked by the people of the principality of "Count Girolamo, her consort" after his death.
It seems the people wanted Countess Forli ousted as the ruler, but she was aided by a fortress until she received help from Milan. Later, when Cesare Borgia attacked her and the people rallied with Borgia against her, her fortress was of no use, thereby proving Machiavelli's point that destroying a fortress can have greater strategic benefit than keeping it.