In an early Quattrocento tract, the De tyranno, Coluccio Salutati, Chancellor of the Florentine Republic, defended Dante's damnation of the assassins of Caesar, and offered a thorough condemnation of the flaws of the Roman Republic and a spirited endorsement of the succeeding autocracy. Salutati's apparent conversion to Dante's Christian Monarchism has puzzled scholars and has led to his characterisation as a somewhat outmoded figure. But a more complex picture emerges from an analysis of an overlooked feature of the De tyranno: its extraordinary use of Lucan's historical epic, the De bello civili. While his contemporaries regarded the poem as an anti-Caesarian polemic, Salutati identified and exploited the ironies of this deeply ambivalent work toward the republican ideal it was taken to espouse. Through a strategy of quotation, allusion, and paraphrase, he expressed his own monarchist arguments in the language of the favourite literary authority of Renaissance republicanism. This strategy was apparently original and probably influential, and is detectable, too, in Salutati's other works. These borrowings demonstrate the degree of dexterity with which a Florentine humanist might apply the classical learning of the Trecento to the political debates of the Quattrocento, and also the undiminished powers of the ageing Chancellor as reader and rhetorician.