Congo Arab war The Congo Arab war ( also known as the Belgo - Arab War ) took place in what is now the Democratic Republic of the Congo between the forces of Belgian King Leopold II ' s Congo Free State and various Zanzibari " Arab " slave traders led by Sefu , the son of Tippu Tip . Fighting occurred in the eastern Congo between 1892 and 1894 . It was a proxy war , with most of the fighting being done by native Congolese , who aligned themselves with either side and sometimes switched sides . The causes of the war were mainly economic , since Leopold and the Arabs were contending to gain control of the wealth of the Congo . The war ended in January 1894 with a victory of Leopold ' s forces . Initially King Leopold collaborated with the Arabs but competition over the control of ivory turned his stance to confrontational . The war against the Swahili - Arab economic and political power was presented as a Christian anti - slavery crusade . The Congo Free State ' s regime , however , was much worse than the Arab slavery . Prelude . In 1886 , while Tippu Tip was in Zanzibar , a dispute arose between a Congo Free State fort at Stanley Falls , led by Tip , and a smaller , nearby fort led by Walter Deane and Dubois . Tip ' s men at the Stanley Falls fort alleged that Deane had stolen a slave woman from an Arab officer there . Deane asserted that the girl had fled after being badly beaten by her master , and that he had only offered her refuge . Tip ' s men attacked the fort and after a four - day siege , the defenders ran out of ammunition and fled , abandoning the fort . The Free State made no counterattack , and Tip began to move more men into the Congo , including several Arab slave captains and also some Congolese leaders , such as Gongo Lutete . In March and April 1892 , Tip ' s son Sefu began to lead attacks on various Congo Free State ( CFS ) personnel in the eastern Congo , including the British ivory trader Arthur Hodister and Captain Guillaume Van Kerckhoven , who had been taking ivory by force from Arab traders . Gongo Luteta also led actions in the east at this time , but defected to the Force Publique after suffering a defeat early on . By October 1892 , Sefu was leading a force of 10 , 000 men , some 500 Zanzibari officers and the rest Congolese . The Belgian Force Publique , led by Francis Dhanis , consisted of a few dozen Belgian officers commanding several thousand African auxiliaries . Course of the war . Open warfare broke out in late November 1892 , when Sefu set up a fort on the Lomami River , where he was attacked by the Force Publique and defeated . Dhanis used this battle as a pretext for advancing against the Arabs in force . He allowed his army to travel with all of their wives , slaves , and servants , who did all of the army ' s cooking and cleaning and acted as a supply train . In addition , he did not allow his men to harm local non - combatants , earning him goodwill of the local Congolese people . In early 1893 the Free State took the key river city of Nyangwe after a 6 - week siege that devastated the city . Of 1000 original buildings in the city , only one remained standing after the siege . Later , Free State forces took Kasongo , in the north . The war ' s last major battle occurred on 20 October 1893 , on the Luama River , west of Lake Tanganyika . It was a tactical stalemate , but the Sefu was killed , and the remaining resistance soon fell apart . The war ended in Free State victory by January 1894 .