The murder was, in the penal Renaissance system, one of the crimes that was punished with the death, and that was condamned by the Church because of its violation of the Fifth Commandment: You shall not kill. Just an homicide, and just only one kind of murderer, seems not to have social and religious sen-tence: that one of the execution of the death penalty given by a recognized murderer, the hangman. The purpose of this paper is to analyze this figure of “legal murderer”, highlighting not only who were those that became executioners, and the evolution of their activities over the years, but also the relation among them, and the Renaissance Italian civic and religious societies. That is the relation between their “legal homicide”, and their violation of the Fifth Commandment, as well as the relation between this last one and the social needs to be freed from illegal murderers.