Complex sentence: 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.
Split into simpler sentences: In response to the incidents, a small force of British warships and soldiers were sent to Arabia. The expedition succeeded in defeating the Arab defenders, who held a fortress on Sira Island, and occupied the nearby port of Aden.