During the early part of the war, the brigade was attached to the New Zealand and Australian Division. In mid-May 1915, the brigade was deployed to Gallipoli as reinforcements for the infantry that had landed in April, who had become pinned around a small perimeter around a beachhead at Anzac Cove; deployed in a dismounted role, the brigade was assigned as corps troops directly under the Australian and New Zealand Army Corps. About a quarter of the strength of each light horse regiment remained in Egypt with their horses; however, additional reinforcements were provided prior to their arrival at Gallipoli, to bring them up to strength.