Birdwood took effective command of the Australian Imperial Force, i.e. all Australian Forces in May 1915 while still commanding Allied troops on the ground at Gallipoli. He launched a major attack on the Turks in August 1915 (the Battle of Sari Bair) but still failed to dislodge them from the peninsula. Notwithstanding this he was the only corps commander opposed to abandoning Gallipoli. He was promoted to the permanent rank of lieutenant-general on 28 October 1915 and given command of the newly formed Dardanelles Army: the one outstanding success of the campaign was the evacuation led by Birdwood, which took place in December 1915 and January 1916, when the entire force was withdrawn before any Turkish reaction.