Horseshoe pitching's oldest documented traces in history are often in relation with soldiers.
This picture, one of the most ancient ever found showing Canadian horseshoe pitchers, makes no exception.
Taken during WWI in July 1916, it shows members of the 29th Canadian Infantry Battalion.
Though Library and Archives Canada
describes the picture with the comment "Playing quoits", we can easily recognize the horseshoes on the picture.
The following site (http://www.archive.org/details/CEF_29thBn_1915) tells us more about the battalion:
The 29th Canadian Infantry Battalion was organized in October 1914 under the command of Lieutenant-Colonel J.S. Tobin under authorization published in General Order 36 of 15 March 1915. The battalion was mobilized at Vancouver and recruited in Vancouver and New Westminster. The battalion embarked at Montreal on 20 May 1915 aboard MISSANABIE, disembarking in England on 30 May 1915. Its strength was 37 officers and 1104 other ranks. The battalion arrived in France on 17 September 1915, becoming part of the 2nd Canadian Division, 6th Canadian Infantry Brigade. It was later reinforced by the 1st Canadian Reserve Battalion. The battalion returned to England on 12 April 1919, disembarked in Canada on 16 May 1919, was demobilized on 24 May 1919, and was disbanded by General Order 149 of 15 September 1920.
For more information see also http://en.wikipedia.org/wiki/29th_Battalion,_CEF
see the previous picture of the month.