Canada   Canadian enlisted man’s stiff service cap (WWI) As part of the British Commonwealth, the Canadian Expeditionary Force was a major part of the Allied defense efforts during the First World War. This stiff, service dress (SD) cap belonged to an enlistedman of the Royal Artillery and dates from about 1915. Apart from the side buttons which feature the hallmark maple leaf and the word “Canada,” this cap is identical to the caps used by the British Army.