The Canadian Expeditionary Force

The Canadian Expeditionary Force (CEF) was the field force raised in August 1914 and was the main contribution Canada's army (known then as the Militia) made to the Allied cause in the First World War.

The CEF was a separate entity from the Canadian Militia, and none of the Regiments of the peacetime Canadian forces mobilized for the war. Instead, numbered infantry battalions along with units of the combat arms and supporting arms were created, assembled at Valcartier in Quebec, and sent to the United Kingdom as Contingents. There, they were formed into divisions, five in total; the first four served in France while the fifth was eventually broken up for reinforcements.

The First Canadian Division went to France in February 1915; when the Second Canadian Division arrived in France later that year, the Canadian Corps was formed and was joined in 1916 by the Third Canadian Division and Fourth Canadian Division.

The four Divisions of the Canadian Corps fought together for the first time at Vimy Ridge in April 1917 during the Battle of Arras.

The Canadian Corps, and the CEF, disbanded in 1919. In 1920, the Otter Commission made recommendations on wholesale reorganizations of the Militia, in order that the histories of both the peacetime army and the CEF might be perpetuated.