Before 1669, French colonists in Canada had not been obliged to serve occasionally as soldiers, except in emergency situations. Furthermore, no permanent military organization existed to mobilize them. However, a letter from Louis XIV changed all that. On April 3, 1669, he ordered Courcelles, who was governor at the time, to "divide" his subjects in Canada into companies "with regard for their proximity, and, after having divided them in this way, to select captains, lieutenants and ensigns to command them ... to issue orders that they assemble once a month to practise handling arms." Care should be taken, he added, that these men "always be well armed and always have the powder, lead and fuses necessary to use their arms when needed." 
These few lines marked the official birth of the Canadian militia. They set in motion a general organization and mobilization program that would take many years to complete. It fell to Frontenac, who succeeded Courcelles in 1672, to carry out the considerable organizational work required throughout the colony. In so doing, he certainly drew inspiration from the coastguard militia in France at the time, for the Canadian militia was similar in many ways.
For example, it seemed natural to use parishes as the rallying points. Each parish therefore created its own militia company, with the more populous parishes having several. The structure of these companies was an exact replica of the regular troops. At the head was a captain, assisted by a lieutenant and an ensign, then a few sergeants and corporals, followed by ordinary soldiers. In all, there would be about 50 men per company.
All the parishes were attached to one of the three districts into which the colony was divided: Quebec, Trois-Rivières or Montreal. Each district had a militia staff consisting of a colonel, a lieutenant-colonel and a major. The district governors commanded their local militias, while the governor general of the entire colony was the supreme commander. However, the intendant could requisition militiamen to deal with civilian public duties.
All men between the ages of 16 and 60 who were fit to bear arms had to join the militia company of their parish and participate in its activities. This amounted to between a quarter and a fifth of the colony's total population. There were about 3,500 militiamen in 1710, and by 1750, the militia had grown to 11,687 men, divided into 165 companies commanded by 724 officers and 498 sergeants. Only religious orders and seigneurs were exempt from service, although almost all the latter were officers in either the regular troops or the militia.