A
war of aggression, sometimes also
war of conquest, is a
military conflict waged without the justification of
self-defense, usually for territorial gain and subjugation. The phrase is distinctly modern and diametrically opposed to the prior legal international standard of "
might makes right", under the medieval and pre-historic beliefs of
right of conquest. Since the Korean War of the early 1950s, waging such a
war of aggression is a crime under the
customary international law. Possibly the first trial for waging aggressive war is that of the Sicilian king
Conradin in 1268.