The execution of Charles I Stuart on January 30, 1649, quickly came to be known throughout Europe: for the first time in England history, a king formally in charge had been put to death. Justifying such a decision became a fundamental task for the Parliamentarians. This paper aims to show that classical resistance theories were merged with a language and concepts belonging to the category of religious sacrifice in revolutionary literature. Such a blend between human justice and sacrifice was indeed one of the strategies to justify the execution of Charles I.