History of Sudan association with the single largest political grouping, the [[National Umma Party Sudan|Umma Party]] (once led by a descendant of the Mahdi, [[Sadiq al Mahdi]]). Taking advantage of conditions resulting from Ottoman-Egyptian exploitation and maladministration, the Mahdi led a nationalist revolt culminating in the fall of [[Khartoum]] on 26 January 1885. The interim governor-general of the Sudan, the British Major-General [[Charles George Gordon]], and many of the fifty thousand inhabitants of Khartoum were massacred. The Mahdi died in June 1885. He was followed by [[Abdallahi ibn Muhammad]], known as the [[Caliph|Khalifa]], who began an expansion of Sudan's area into Ethiopia. Following
Khartoum of them diplomats. The US ambassador, the US deputy ambassador, and the Belgian "chargé d'affaires" were murdered. The remaining hostages were released. A 1973 United States Department of State document, declassified in 2006, concluded: "The Khartoum operation was planned and carried out with the full knowledge and personal approval of Yasser Arafat." In 1977, the first oil pipeline between Khartoum and the Port of Sudan was completed. Throughout the 1970s and 1980s, Khartoum was the destination for hundreds of thousands refugees fleeing conflicts in neighboring nations such as Chad, Eritrea, Ethiopia, and Uganda. Many Eritrean and Ethiopian refugees assimilated into