Recent political theory has overlooked the extent to which Machiavelli’s account of factions in 1420s Florence is indebted to another Istorie Fiorentine, by the chronicler Giovanni Cavalcanti. This chapter examines Machiavelli’s Florentine Histories against Cavalcanti’s earlier Istorie, with special attention to the politics surrounding the catasto tax of 1427 – a reform both Machiavelli and Cavalcanti credit with placing the city’s finances before the rule of law, rather than under the control of men. Although the catasto largely failed to live up to its promises, it represents an important early modern attempt at legal and fiscal sovereignty and offers a lens into Machiavelli’s own views of equality before the law. As a disenfranchised magnate who could not meet his tax obligations, Cavalcanti composed portions of his own Istorie Fiorentine from debtors’ prison. Machiavelli’s reliance on the perspective of this embittered nobleman sheds new light on the complicated inter-class competition of Machiavelli’s Histories, and thus on his theory of popular power.