Historical background of the crime of aggresion, in the light of Nuremberg Principles of 1947 and UN General Asembly Resolution of 1974. The Rome Statute, which created an International Criminal Court, enlists the crime of aggression, as one of the four crimes under its ratione materiae competence. Uunlike the other three crimes, the Rome Statute does not define the aggression, untrusting this task to the Assembly of State Parties, as the most important negociating fora of the Court. The Kampala Amendements, issued as a result of those negotiations, offer a significant distinction between the definition of the crime of aggression, imputable to a person, which fells under the ICC specific competence, and the aggression as an act of a state. The principle of universal jurisdiction, applied in light of the complementarity betwen ICC and national courts, represents an important additional avenue towards impunity, an efective means to discourage aggression, as an individual crime and as a crime of a state.