Believed to be the shortest war in recorded history, the Anglo-Zanzibar War began at 9:00 AM on August 27, 1896, and lasted for 37 to 45 minutes. Conflict Summary: The Anglo-Zanzibar War commenced after the death of the pro-British sultan of Zanzibar, Hamad bin Thuwaini, on August 25, 1896.

http://militaryhistory.about.com/od/battleswars1800s/p/anglozanzibar.htm