Nyasaland became heavily involved in the First World War – some 19,000 Nyasaland Africans served in the King's African Rifles, and up to 200,000 others were forced to be porters for varying periods, mostly in the East African Campaign against the Germans in German East Africa, where disease caused many casualties among them. This, together with other sources of conflict, resulted in the failed Chilembwe uprising in January 1915, led by the pastor John Chilembwe.