(also known as the Dardanelles operation of 1915), the attempt by the Anglo-French fleet and landing forces from Feb. 19, 1915, to Jan. 9, 1916, during World War I to capture the Dardanelles and the Bosporus and Constantinople, to force Turkey to abandon the war, and to restore communications with Russia through the Black Sea.
Beginning on February 19, the Anglo-French squadron (11 battleships, one battle cruiser, four cruisers, 16 destroyers, and others; later as many as 18 battleships, 12 cruisers, 40 destroyers, and others) bombarded the Turkish forts. However, its attempt on March 18 to force its way through the straits ended in failure with the loss of three ships. It was then decided to capture Gallipoli by a landing. On April 25 a landing force (4 ½ divisions: more than 80,000 men and 178 guns) under the command of the British general I. Hamilton and the French general d’Amade, after losing 18,000 men, made a landing on the Gallipoli Peninsula near Seddul Bahr and another to the north of the first. Attempts to extend the beachheads were unsuccessful because of stubborn resistance by the Turkish troops (five divisions) under the command of the German general Liman von Sanders. Offensive actions by the Anglo-French army during April, May, and June also ended in failure.
At the beginning of August the Allies increased their forces to 12 divisions and began a new offensive during August 6–10; on August 7 they made a landing in Suvla Bay. These strikes were also repulsed by the Turkish troops (15 divisions). From Dec. 10, 1915, through Jan. 9, 1916, the Anglo-French army was evacuated to Salonika in order to reinforce the front there. Allied losses were 145,000 men, whereas the Turks suffered casualties of 186,000 men.
Because of poor preparation and inept leadership of these actions, the lack of a unified command and an overall plan, and squabbles among the Allies, the Gallipoli Expedition did not achieve its goal. Its failure facilitated Bulgaria’s entry into the war on the side of Germany (Oct. 14, 1915).