On January 9, 1916, Allied forces complete their full retreat from the shores of the Gallipoli Peninsula in Turkey, ending a disastrous invasion of the Ottoman Empire. The Gallipoli Campaign resulted in 250,000 Allied casualties and greatly discredited Allied military command. Roughly an equal number of Turks were killed or wounded.
In early 1915, the British government resolved to ease Turkish pressure on the Russians in the Caucasus front by seizing control of the Dardanelles channel, the Gallipoli Peninsula, and then Istanbul. From there, pressure could be brought on Austria-Hungary, forcing the Central Powers to divert troops from the western front. The first lord of the Admiralty, Winston Churchill, strongly supported the plan, and in February 1915 French and British ships began bombarding the Turkish forts guarding the Dardanelles.