The 1st Mounted Rifles (Canterbury Yeomanry Cavalry) was formed on March 17, 1911. They were mobilised during World War I as a squadron of the Canterbury Mounted Rifle Regiment. They served in the Middle Eastern theatre of World War I and first saw action during the Battle of Gallipoli. As a part of the larger New Zealand Mounted Rifles Brigade (of the ANZAC Mounted Division) they went on to serve in the Sinai and Palestine Campaign.