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.