immigrants, which meant anybody arriving in Mongalla and wishing to go north from the Uganda or the Belgian Congo could be examined for sleeping sickness by a medical officer. The maximum punishment for any breach of the new regulations was a £10 fine or a 6-month prison sentence. On 7 December 1917 the last of the northern Sudanese troops were withdrawn from Mongalla, replaced by Equatorial troops. These southern and at least nominally Christian troops remained the only permanent garrison of the town and province until their mutiny in August 1955. When Hasan Sharif, son of Khalifa Muhammad Sahif, was exiled to Mongalla in 1915 after taking place in a conspiracy in Omdurman, Governor Owen said "...I told him he is lucky to come and see this part of Sudan for nothing, when tourists pay hundreds of pounds ... I fear he doesn't see the joke...". Owen retired in 1918. Major Cecil Stephen Northcote succeeded him as Governor of Mongala from 1918 to 1919, then moved on to become Governor of the Nuba Mountains province. The Sudan was very lightly administered. As late as 1919 there were just 17 British administrators in the Bahr al-Ghazal and Mongalla provinces, with a combined area twice that of Britain. In the early years, British officials depended on native officials for advice and to act as interpreters. However, they had to be careful about ethnic rivalries. Thus Fadl el-Mula, a Dinka who had been a police quartermaster, greatly impressed the Governor of Mongalla and was appointed assistant superintendent of the Twic Dinka in 1909. He was credited with keeping the peace between the Dinka and the Nuer people, two groups with a history of fighting and cattle raiding. However, Fadl el-Mula was so strongly biased towards the Dinka that his police were attacked by angry Nuer and he had to be removed from his post. The Arabic language and the Muslim religion continued to be spread in South Sudan by merchants and administrators from the North, and even by British officials who preferred to speak Arabic rather than learn the local language. A rising by the Aliab Dinka in 1919 was suppressed harshly in 1920. That year the Nuer were attacking both the Dinka and the Burun people on the border with Ethiopia. The governor of Mongalla in 1920, V.R. Woodland, said that Mongalla at the time was "in such a muck-up state he