When Great Britain went to war with the Russian Empire in 1854, she was forced to withdraw a great number of troops from Canadian soil to form a Crimean Expeditionary Force. By the Spring of 1855 there were only 1,887 British troops in Upper and Lower Canada, and 1,397 in the Maritimes. Canadians came to the realization that should hostilities develop with the United States, she would have to be almost completely self-reliant for defense. 

Accordingly, a commission was appointed in 1855 to determine the best course of action to raise a new Canadian defense force. It put forth several plans for the expansion of the militia, and while it supported the retention of the old Sedentary (compulsory) militia, it also recommended that a volunteer force be raised, trained and uniformed much along the same lines as today's Canadian Forces Reserve. This new force was to be made up of proper proportions of artillery, cavalry and rifles. Additionally, arms and ammunition to supply a force of 100,000 was to be stockpiled in case of national emergency.

These recommendations were summed up in a bill presented to the Canadian legislature. It expressly retained compulsory service as the principle upon which Canadian defense should be hinged. It also divided the country in 18 military districts, each with battalion and regimental sub-districts, to facilitate mobilization. The principle unit was, as it had always been, the company, and raising the required men was the responsibility of the company commander. Each district was commanded by a colonel, who was assisted by an unpaid staff. The colonel was had to answer to the the paid staff comprising the Adjutant-General and two Deputy Adjutant-Generals, one each for Canada East and Canada West.

The first Adjutant-General was Colonel Baron de Rottenberg. The two Deputy Adjutant-Generals were Lieutenant-Colonel Melchoir-Alphonse de Salaberry and Lieutenant-Colonel Donald MacDonald.

In principle the bill had hardly departed from the traditional Canadian militia organization established in the days of Frontenac and d'Iberville. The major innovation was the creation of the "Active Militia", consisting of 16 troops of cavalry, seven field batteries, five companies of artillery and 50 companies of riflemen, totalling a number not exceeding 5,000 men. All were uniformed volunteers and trained for ten days a year (twenty for artillerists) at public expense. 

This was a real departure. Although Sir Isaac Brock, hero of the War of 1812, had proposed a similar concept in 1812, and various small volunteer organizations had come and gone since 1815, this was the beginning of a true volunteer system in the Canadian military. It became wildly popular, and the clause of compulsory service gradually fell into disuse. In 1856 the governor was granted powers to dispense with the annual compulsory muster, and the concept was completely eliminated in 1950. 

The enthusiasm for all things military sparked by the Crimean War resulted in Canadians flocking to the colours at an unprecedented scale. Before long, an amendment was passed to the bill authorizing the establishment of additional companies of riflemen, although these were to be unpaid. Still, the enthusiasm for such units did not falter. 

Of the 22 units formed in 1855, eighteen still exist today in some form or another, including such famous regiments as the Queen's Own Rifles of Canada and the Canadian Grenadier Guards.