Procedure and justice in the Italian cities of the late middle ages (twelfth-fourteenth centuries) -- How procedures think : facts and the trial -- The accusatory system in action : Bologna between the thirteenth and fourteenth centuries -- Peace accord and trial in the judicial system : the example of Perugia -- How the inquisition is constructed: arbitrium and power in Perugia -- The inquisitorial trial in the political struggles in Bologna between the Duecento and Trecento -- The petition to the Signore and the power of mercy.