The Anglo-Zanzibar War was fought between the United Kingdom and Zanzibar on 27 August 1896. The conflict lasted approximately 38 minutes and is the shortest war in history. The immediate cause of the war was the death of the pro-British Sultan Hamad bin Thuwaini on 25 August 1896 and the subsequent succession of Sultan Khalid bin Barghash. The British authorities preferred Hamud bin Muhammed as Sultan. In accordance with a treaty signed in 1886, a condition for accession to the sultanate was that the candidate obtain the permission of the British Consul, and Khalid had not fulfilled this requirement. The British considered this a casus belli and sent an ultimatum to Khalid demanding that he order his forces to stand down and leave the palace. In response, Khalid called up his palace guard and barricaded himself inside the palace.
The ultimatum expired at 09:00 East Africa Time (EAT) on 27 August, by which time the British had gathered three cruisers, two gunships, 150 marines and sailors, and 900 Zanzibaris in the harbour area. The Royal Navy contingent were under the command of Rear-Admiral Harry Rawson whilst their Zanzibaris were commanded by Brigadier-General Lloyd Mathews of the Zanzibar army.