The Iroquois Confederacy united the Mohawk, Oneida, Onondaga, Cayuga, and Seneca tribes. Sometime, perhaps around 1570, the five tribes had agreed to organize a confederation. They had an elaborate government structure. At its peak each tribe got one vote in the grand council and decisions had to be unanimous. Why did they form this confederation? Probably because they were under attack from all sides by more powerful tribes. They concentrated in remote areas of central New York, building fortified villages on high ground.
Then they began to make a cult out of personal glory in warfare. (Cultural values matter.) The women of the tribes took over the farming duties. This freed up the men for other activities. Today it would be sitting in the recliner drinking a beer and watching sports. For the Iroquois it was ranging through the forests to fight people. Either you get good at this or you get dead. The Iroquois got good at it. Really, really good. A total population of about 12,000 could produce 2,200 warriors at any one time.
At this time Europeans wanted beaver pelts in immense quantities. (They made really sharp-looking and water-proof hats.) Traders were taking 10,000 beaver a year out of upstate New York. They were willing to pay Indian trappers a lot to get the pelts to satisfy the demand in Europe. The first Iroquois treaty was with the French in 1624. The two groups then fell out over the high price of French goods and the French favoritism for the Algonkins and Hurons, who seemed willing to accept Jesuit missionaries. Also, the French did not want to sell the Iroquois guns. The Iroquois got in touch with the Dutch fur traders on the Hudson River. The Dutch tried to trade alcohol for furs. The Iroquois wanted guns. So the Dutch sold guns.
By the 1630s the over-hunting of beaver on Iroquois land threatened to undermine the economic basis of confederation power. What to do? Perhaps we should work to create a “sustainable” economy in harmony with Nature, instead of engaging in thoughtless resource depletion. Perhaps we should reject consumerism, which puts a premium on “having things” at the expense of emphasizing nurturing relationships with the friends and family who give life real meaning. Nope. There’s lots of beaver on the lands of other tribes. We’re going to conquer those tribes and take their beaver.
Between 1648 and 1675 they were on the offensive. In a quarter of a century they smashed up all the major tribes to their west as far as Ohio and as far south as Georgia. This gave them control of all the fur trade of the northern forests. Tribes moving furs from up-country either paid a share to the Iroquois or they made a long detour to avoid coming into contact with the Iroquois. Either way the “tax” on the fur trade pushed up the price of furs delivered in Montreal. This greatly annoyed the French. Anyway, between this and the butchering of Jesuit missionaries, the French got all bent out of shape with the Iroquois. They launched several major invasions of Iroquois country. This, in turn, greatly annoyed the Iroquois, who launched a whole series of raids against the French settlers in Canada.
Once the British got New York away from the Dutch, they started dealing with the Iroquois. When France and Britain fought for control of North America, the Iroquois provided a valuable ally to the British. (Certainly a lot more valuable than the useless American colonists who were afraid of the woods.) The British would give you the guns for free, then they would pay for scalps on top of that. Iroquois heaven.