The Dardanelles, a narrow 60-mile-long strip of water that divides Europe from Asia, has been of great strategic significance for centuries. Carefully secured by international treaty, it was the closing of the Dardanelles that eventually brought the Ottoman Empire into the war as a German ally at the end of October 1914.
By late 1914, movement on the Western Front had ground to a halt. Some Allied leaders suggested opening new fronts to break the deadlock, shorten the war and avoid heavier loss of life. Soon after the start of the new year, Great Britain and France attempted to force the Dardanelles and attack Constantinople (now Istanbul), the capital of the Ottoman Empire.
Many in Britain, notably the First Lord of the Admiralty, Winston Churchill, believed that knocking the Ottomans out of the war would undermine Germany. They theorised that as a result of this attack, Britain and France would be able to help their weakest partner, Russia; that the Suez Canal and Britain’s Middle Eastern oil interests would be secured; and that undecided Balkan states, including Bulgaria and Greece, would join the Allied side. It was an exciting and alluring proposition. But it was based on the mistaken belief that the Ottomans were weak and could easily be overcome.
On 19 February 1915, British and French ships began a naval assault on the Dardanelles. The fighting culminated in a heavy setback for the Allies on 18 March due to large losses from Turkish mines. Military landings on the Gallipoli peninsula followed on 25 April. Contained by the Ottoman defenders, a new assault began on 6 August. Each fresh attempt was defeated, and by mid-January 1916, all Allied troops had been evacuated and the attack on the Dardanelles abandoned.
For the Ottomans, it was a major achievement. The Allies succeeded only in attrition, killing thousands of Ottoman soldiers. Even this exacted a high price; total casualties for the campaign were more than half a million. The Dardanelles campaign remains one of the First World War’s most controversial episodes.