Answer: The Turks fought fiercely and successfully defended the Gallipoli Peninsula against a massive Allied invasion in 1915-1916, but by 1918 defeat by invading British and Russian forces and an Arab revolt had combined to destroy the Ottoman economy and devastate its land, leaving some six million people dead and millions. Finally, after fighting on the side of Germany in World War I and suffering defeat, the empire was dismantled by treaty and came to an end in 1922, when the last Ottoman Sultan, Mehmed VI, was deposed and left the capital of Constantinople (now Istanbul) in a British warship.