The center and soul of the economic system in New France was the traffic in furs. Even before the colony contained more than a handful of settlers, the profit-making possibilities of this trade were recognized. It grew rapidly even in the early days, and for more than a hundred and fifty years furnished New France with its sinews of war and peace. Beginning on the St. Lawrence, this trade moved westward along the Great Lakes, until toward the end of the seventeenth century it passed to the headwaters of the Mississippi. During the two administrations of Frontenac the fur traffic grew to large proportions, nor did it show much sign of shrinking for a generation thereafter. With the ebb-tide of French military power, however, the trader's hold on these western lands began to relax, and before the final overthrow of New France it had become greatly weakened.

In establishing commercial relations with the Indians, the French voyageur on the St. Lawrence had several marked advantages over his English and Dutch neighbors. By temperament he was better adapted than they to be a pioneer of trade. No race was more supple than his own in conforming its ways to the varied demands of place and time. When he was among the Indians, the Frenchman tried to act like one of them, and he soon developed in all the arts of forest life a skill which rivaled that of the Indian himself. The fascination of life in the untamed wilderness with its hair-raising experiences, its romance, its free abandon, appealed more strongly to the French temperament than to that of any other European race. Non licet omnibus adire Corinthum. And the French colonist of the seventeenth century had the qualities of personal courage and hardihood which enabled him to enjoy this life to the utmost.

Then there was the Jesuit missionary. He was the first to visit the Indians in their own abodes, the first to make his home among them, the first to master their language and to understand their habits of mind. This sympathetic comprehension gave the Jesuit a great influence in the councils of the savages. While first of all a soldier of the Cross, the missionary never forgot, however, that he was also a sentinel doing outpost duty for his own race. Apostle he was, but patriot too. Besides, it was to the spiritual interest of the missionary to keep his flock in contact with the French alone; for if they became acquainted with the English they would soon come under the smirch of heresy. To prevent the Indians from engaging in any commercial dealings with Dutch or English heretics meant encouraging them to trade exclusively with the French. In this way the Jesuit became one of the most zealous of helpers in carrying out the French program for diverting to Montreal the entire fur trade of the western regions. He was thus not only a pioneer of the faith but at the same time a pathfinder of commercial empire. It is true, no doubt, that this service to the trading interests of the colony was but ill-requited by those whom it benefited most. The trader too often repaid the missionary in pretty poor coin by bringing the curse of the liquor traffic to his doors, and by giving denial by shameless conduct to all the good father's moral teachings. In spite of such inevitable drawbacks, the Jesuit rendered a great service to the trading interests of New France, far greater indeed than he ever claimed or received credit for.

In the struggle for the control of the fur trade geographical advantages lay with the French. They had two excellent routes from Montreal directly into the richest beaver lands of the continent. One of these, by way of the Ottawa and Mattawa rivers, had the drawback of an overland portage, but on the other hand the whole route was reasonably safe from interruption by Iroquois or English attack. The other route, by way of the upper St. Lawrence and the lakes, passed Cataraqui, Niagara, and Detroit on the way to Michilimackinac or to Green Bay. This was an all-water route, save for the short detour around the falls at Niagara, but it had the disadvantage of passing, for a long stretch, within easy reach of Iroquois interference. The French soon realized, however, that this lake route was the main artery of the colony's fur trade and must be kept open at any cost. They accordingly entrenched themselves at all the strategic points along the route. Fort Frontenac at Cataraqui was built in 1674; the fortified post at Detroit, in 1686; the fort at Niagara, in 1678; and the establishments at the Sault Ste. Marie and at Michilimackinac had been constructed even earlier.

But these places only marked the main channels through which the trade passed. The real sources of the fur supply were in the great regions now covered by the states of Ohio, Wisconsin, Iowa, and Minnesota. As it became increasingly necessary that the French should gain a firm footing in these territories as well, they proceeded to establish their outposts without delay. The post at Baye des Puants (Green Bay) was established before 1685; then in rapid succession came trading stockades in the very heart of the beaver lands, Fort St. Antoine, Fort St. Nicholas, Fort St. Croix, Fort Perrot, Port St. Louis, and several others. No one can study the map of this western country as it was in 1700 without realizing what a strangle-hold the French had achieved upon all the vital arteries of its trade.