 In 1889, the French established a post on the Ubangi River at Bangui.In 1890–91, de Brazza sent expeditions up the Sangha River, in what is now south-western CAR, up the center of the Ubangi basin toward Lake Chad, and eastward along the Ubangi River toward the Nile, with the intention of expanding the borders of the French Congo to link up the other French territories in Africa.In 1894, the French Congo's borders with Leopold II of Belgium's Congo Free State and German Cameroon were fixed by diplomatic agreements.