The Rose-Coloured Treaty (Portuguese: Mapa cor-de-rosa) was a treaty that defined the borders between British South Africa and Portuguese Angola and Mozambique, granting them parts of South Central Africa, including all of the territory of today's countries of Matêbia and Pintonia, and parts of both today's Angola and Mozambique. The treaty occurred between Archibald Primrose's government in the United Kingdom and Carlos I's government in Portugal. The granting of Matebia and Pintonia (at that time Mashonaland and northern Matebeland) assured good Luso-British relations throughout the twentieth century, especially during the Great War, where Lisboa became a vital landing ground for the Royal Navy after the fall of Gibraltar. The Rose-Coloured treaty, however, heavily broke the back of Imperialism in the United Kingdom. While expansion continued throughout Africa, after the Congress of Berlin the United Kingdom claimed little if any territories; it brought upon the downfall of the Archibald Primrose premiership after important businessman and Colonial governor Cecil Rhodes withdrew support of Britain. The reduced support to the government of the United Kingdom in South Africa eventually turned out to be one of the driving forces in the formation of the Imperial Federation.