Uti possidetis Uti possidetis ( Latin for " as you possess " ) is a principle in international law that territory and other property remains with its possessor at the end of a conflict , unless otherwise provided for by treaty ; if such a treaty does not include conditions regarding the possession of property and territory taken during the war , then the principle of uti possidetis will prevail . Originating in Roman law , the phrase is derived from the Latin expression " uti possidetis , ita possideatis " , meaning " may you continue to possess such as you do possess " ( lit . , " as you possess , thus may you possess " ) . This principle enables a belligerent party to claim territory that it has acquired by war . In the early 17th century , the term was used by England ' s James I to state that while he recognized the existence of Spanish authority in those regions of the Western Hemisphere where Spain exercised effective control , he refused to recognize Spanish claims to exclusive possession of all territory west of longitude 46° 37 ' W under the Treaty of Tordesillas . More recently , the principle has been used in a modified form ( see " Uti possidetis juris " ) to establish the frontiers of newly independent states following decolonization , by ensuring that the frontiers followed the original boundaries of the old colonial territories from which they emerged . This use originated in South America in the 19th century with the withdrawal of the Spanish Empire . By declaring that " uti possidetis " applied , the new states sought to ensure that there was no " terra nullius " in South America when the Spanish withdrew and to reduce the likelihood of border wars between the newly independent states and the establishment of new European colonies . The same principle was applied to Africa and Asia following the withdrawal of European powers from those continents , and in locations such as the former Yugoslavia and the Soviet Union where former centralized governments fell , and constituent states gained independence . In 1964 the Organisation of African Unity passed a resolution stating that the principle of stability of borders — the key principle of " uti possidetis " — would be applied across Africa . Most of Africa was already independent by this time , so the resolution was principally a political directive to settle disputes by treaty based on pre - existing borders rather than by resorting to force . To date , adherence to this principle has allowed African countries to avoid border wars ; the notable exception , the Eritrean – Ethiopian War of 1998 – 2000 , had its roots in a secession from an independent African country rather than a conflict between two decolonized neighbours . On the other hand , the colonial boundaries often did not follow ethnic lines , and this has helped lead to violent and bloody civil wars among differing ethnic groups in many post - colonial ( and post - Communist ) countries , including Sudan , the Democratic Republic of the Congo , Angola , Nigeria , Uganda , Georgia , Azerbaijan , Moldova and the former Yugoslavia . The principle was affirmed by the International Court of Justice in the 1986 Case " Burkina - Faso v Mali " :