The light horse regiments' first involvement in the fighting during the war came during the Gallipoli Campaign, where the troops of the 1st, 2nd and 3rd Light Horse Brigades were sent to Gallipoli without their horses to provide reinforcements for the infantry. During the campaign they were used mainly in a defensive role, although the light horsemen did participate in several costly battles, such as the Battle of the Nek. After the evacuation of the Gallipoli peninsula in December 1915, the light horse regiments that had been deployed were re-constituted in Egypt and in March 1916, the Australian mounted troops of the 1st, 2nd and 3rd Light Horse Brigades and the New Zealand Mounted Rifles Brigade were placed together in the Anzac Mounted Division.