The contribution analyzes the nature of the relationship between interpersonal violence and justice in late communal Italy, focusing on the ways in which the new legislation on revenge developed from the mid-13th century influenced the practices of conducting and managing conflicts in the judiciary. We examine a criminal trial carried out in Bologna in 1306 against two Florentines accused of having committed an assault motivated by retaliation against a white Florentine exile then resident in the university city. This case study also sheds light on the practical consequences of the intersection between politics and justice – a phenomenon that was increasingly frequent in Bologna and other cities starting from the early fourteenth century.