It was a result of the 1750 Treaty of Madrid, which set a line of demarcation between Spanish and Portuguese colonial territory in South America.[1] In 1754 the Jesuits surrendered control of the missions, but the Guaraní peoples, led by Sepé Tiaraju, refused to comply with the order to relocate.[5] The treaty ceded the outpost of Colonia del Sacramento to Spain and set the border between the two colonial empires as the Uruguay River.The Guaraní living in the seven mission settlements refused to move out of the lands that were ceded to Portugal, or to accept Portuguese rule.[6] There was inconclusive fighting throughout 1754 between Guaraní rebels under Sepé Tiaraju and the combined Portuguese and Spanish forces commanded by Gomes Freire de Andrade.