 One of the most notable figures to take up this agenda was Coluccio Salutati (1331–1406) in a treatise entitled De tyranno (On Tyranny; 1400 [1927]. Salutati had been not only Bruni’s instructor but also his immediate predecessor as Chancellor of the Florentine republic. In the view of Salutati, there are valid reasons that one should stand prepared to countenance tyrannical rulers at times. In support of what might seem at first glance an odd position for a humanist to embrace, he introduces a distinction between two types of tyrants: those who rule without valid title (usurpers) and those who possess a legitimate claim to office but use their powers unlawfully and unjustly as a result of their prideful characters. This difference is decisive for Salutati, whose main concern is with the propriety of slaying tyrants in general and with the murder of Julius Caesar in particular.