The definition of military occupation has been disputed in terms of the core meaning ascribed to it and even in terms of the appropriateness of the term itself, with some commentators preferring the term ‘belligerent occupation’, in continuation of the Roman idea of occupatio bellica. Where such preference has been expressed, it has been acknowledged that there are other types of military occupation. That same preference and concession is repeated in the British Manual of the Law of Armed Conflict, according to which ‘classically, this [belligerent occupation] refers to the occupation of enemy territory, that is, when a belligerent in an armed conflict is in control of some of the adversary's territory and is directly responsible for administering that territory’. This manual includes occupation of neutral territory during wartime in belligerent occupation, but excludes liberation of allied territory, international administration of territory under such organisations as the United Nations and the presence of armed forces in another state in accordance with some treaty or agreement. Obviously, the core meaning ascribed to occupation will affect the extent of the range of types of occupation, with belligerent occupation suggesting a narrower range than the more expansive term military occupation. Yet the two issues, of the core meaning and the range of types of occupation, have not received the same consistency of attention. The first systematic study of military occupation beyond war, by Raymond Robin, was not published until 1913.