Southern Sudan's remote and undeveloped provinces—Equatoria, Bahr al Ghazal, and Upper Nile—received little official attention until after World War I, however, except for efforts to suppress tribal warfare and the slave trade. The British justified this policy by claiming that the south was not ready for exposure to the modern world. To allow the south to develop along indigenous lines, the British, therefore, closed the region to outsiders. As a result, the south remained isolated. A few Arab merchants controlled the region's limited commercial activities while Arab bureaucrats administered whatever laws existed. Christian missionaries, who operated schools and medical clinics, provided limited social services in southern Sudan.