 According to Salutati, the appropriate treatment of a tyrant is wholly dependent upon whether or not he is a usurper. If so, then those subject to him may invoke the Roman law principle that it is “lawful to repel by force the assailant of an individual or a piece of property and if he persists, to kill him” in order to justify resistance to a tyrant. By contrast, Salutati condemns those who argue that wicked princes ought to be killed even when they hold their office by right. He asserts that only the public authority that placed a ruler in office (whether a superior or the community) enjoys the right to remove him from power; private persons, acting in their own right, have no say in the matter.