The Aden Expedition was a naval operation carried out by the British Royal Navy in January 1839. Following Britain's treaty concerning the colonization of territory in the present day Yemen, the Sultanate of Lahej resisted which led to a series of skirmishes between the two sides. In response to the incidents, a small force of British warships and soldiers were sent to Arabia which succeeded in defeating the Arab defenders, who held a fortress on Sira Island, and occupied the nearby port of Aden.