Disposition, administration and possession of territory have occurred throughout of the history of mankind, often resulting all together in conquest and annexation. In more modern times the peace treaties of Osnabrück and Münster in 1648 (Westphalian Peace), ending the war of the “Thirty Years” in Europe, brought a new structure and means in the relations between the European states. A new époque started by the Vienna Congress in 1815 following the wars of Napoleon and was also the beginning of the so-called European Concert conducted by the “Great Powers” in arranging territorial issues in Europe. This era was concluded by the Versailles Peace Treaty in 1919, which also brought a new player into the “territorial business”, namely the League of Nations/Société des Nations, that is to say an international organization.

After the Second World War the United Nations (UN)/l’Organisation des Nations Unies (ONU) was created and given such a position that the powers once held by the “Great Powers” to a certain extent now have been channeled through the UN. Consequently, considering the main objective of the UN, that is to preserve international peace and security or to restore such conditions, the UN has engaged itself in almost countless missions to that end. In many cases the use of disposition, administration and possession of territory on the part of the UN has taken place, including state-building. This Study focuses on the actions by the UN concerning the three mentioned aspects, including a discussion on a number of legal issues pertaining to territory.