The Battle of Gallipoli or the Battle of Çanakkale was a campaign of the First World War that took place on the Gallipoli peninsula. In January 1916, after eight months' fighting, with approximately 250,000 casualties on each side, the land campaign was abandoned, and the invasion force withdrew. It was a costly defeat for the Allies and the sponsors. The campaign was considered a tremendous Ottoman victory. In Turkey, it is regarded as a defining moment in the history of the state, a final surge in defence of the motherland as the Ottoman Empire retreated. The struggle formed the basis for the Turkish War of Independence and the declaration of the Republic of Turkey eight years later, with Mustafa Kemal Atatürk, who rose to prominence as a commander at Gallipoli, founder and president.