By mid-1915, the recruits were judged to be ready for active service, and the division sailed for the Mediterranean in June-July 1915. As part of the Suvla Bay landing force, it reinforced the British expeditionary force at Gallipoli, on 7 August. The 6th (Service) Battalion, Alexandra, Princess of Wales Own (Yorkshire Regiment) (32nd Brigade) was the first "Kitchener unit" to be involved in a major offensive operation of the war. Its action at Lala Baba Hill, on 7 August, was costly: all but three of its officers were killed, including the CO, Colonel E. H. Chapman, were killed. Afterwards the hill was known to the Allies as York Hill. The division continued to serve at Gallipoli, suffering high casualties, until the evacuation of Suvla in December 1915. It then spent a period of time in Egypt, guarding the Suez Canal.