Iroquoian society had many levels and could split at any one of them. Each family in a tribe belonged to a clan, each headed by a clan mother. When a man married, he moved into his wife's clan and longhouse. The wife owned the family property and their children belonged to the mother's clan. However, any person, clan, village or tribe could disagree with any decision at any level and could ignore it. So if the Senecas wanted to wage war on the Hurons, they were free to do so even if the Mohawks were against it. This became important in the Revolutionary War and the War of 1812, when tribes took different sides and even parts of tribes took different sides.

Unlike Algonquian tribes such as the Mississauga, Iroquois were not nomadic. Their villages were permanent until the soil became worn out, at which time the village moved a short distance. The Iroquois were basically farmers, or rather the women were, because they did all of the farm work. Men did all of the hunting and fighting. There were two types of chief: peace and war. Peace chiefs were elected by clan mothers from "royal" family lines so they were basically hereditary. Henry Tekarihogen was a peace chief of the Mohawks. When he died, John Brant was elected as Tekarihogen through Catherine Brant, Joseph's widow and John's mother, who was a clan matron and related to Henry Teharihogen. Joseph Brant was a war chief and became one through his leadership and fighting abilities. Peace chiefs could not lead in war and war chiefs could not lead in peace, except Joseph Brant, who led in both war and peace.

The accepted date for the founding of the Five Nations is about 1570, when the Huron holy man Deganawida had a vision of peace and cooperation between Iroquois tribes. Despite a language or speech problem, he managed to persuade Hiawatha, the great Mohawk chief, to support him, supposedly conjuring up a solar eclipse as a clincher. The Five Nations were only required to keep peace among themselves; they could and did make war with others, including other Iroquois. At the height of their power about 1680, they ruled an area from Lake Superior to the Atlantic and from Central Ontario to the Carolinas. They did not occupy that territory though, they always returned to their traditional homeland in Northern New York State.

The arrival of Europeans brought disease and more warfare and the number of fighting men declined considerably. The Five Nations response was to absorb men from defeated Iroquois tribes into their ranks. They even absorbed the whole Tuscarora tribe to become the Six Nations, although the Tuscarora were never equals and had no vote at the central council. Men absorbed into the community were regarded as second-class citizens and never completely accepted. Eventually, some of these people, mainly Senecas and Cayugas, left the Five Nations and moved west to Ohio, where they became known as Mingos, after the Delaware word "minqua" meaning "treacherous". Some members of the Five Nations were converted to Catholicism by the French and moved to the St Lawrence, where they became known as Caughnawagas. They later expanded into several reserves and became known as the Seven Nations.

The end of the Six Nations Confederation started with the American Revolution. In 1774, at exactly the wrong time, the great Indian agent, Sir William Johnson, one of the few Europeans who was trusted, died after making a speech to the Mohawks. His protégé, Joseph Brant, was convinced that if the Americans won, they would take the land from the Six Nations. The central council, however, wanted to remain neutral, regarding the war as a white man's war. Both the British and the Americans used blackmail, bribes, and threats to try move the Six Nations to their side. When Sir William's son, Sir John Johnson, was arrested for being loyal to the crown, Brant moved his warriors north to the British. Then occurred a period of atrocities on both side. For every Cherry Valley massacre on one side, there was a Gnadenhutten massacre on the other. For every Joseph Brant, there was a General Sullivan. At the end of the war, the Six Nations was split into many pieces. Some families moved north to the Grand River and Prince Edward County in Ontario. Others tried to stay in their tradition homeland, only to have the land taken from them under dubious circumstances. Others were shipped off to Wisconsin or Oklahoma.

Governor Haldimand probably exceeded his mandate when he "granted" the Six Nations the land on the Grand River: six miles on both sides of the river from what they thought was the source to the mouth. For many years, the Six Nations fought for the right to sell the land as they wished, only for the government to stall and delay, as governments are extremely expert at doing. When the treaty to end the war was signed, there was no mention of the Six Nations and their land. The Six Nations felt they had been betrayed so that when the War of 1812 started, the Six Nations decided to remain neutral.

This time it was John Norton, Scottish-born and part-Cherokee, now a Mohawk war chief, who reprised the Joseph Brant role when he led his Mohawk warriors to Detroit in support of General Brock's extraordinary attack. Everyone likes to be a winner and so too do the Iroquois of the Grand River, so when Brock emerged victorious with the support of Norton and his few Grand River people, the rest of the Grand River warriors warmed to the idea of supporting the British. It was just as well for, without the support of the Six Nations, the outcome at the Battle of Queenston Heights might have been different. After Brock had been killed, Norton and his warriors pinned down the Americans on the Queenston Heights until Sheaffe and his reinforcements arrived and ultimately defeated the Americans.

When the British were forced out of Fort George in 1813, the Grand River warriors became fearful for their homes and families now in danger. Many warriors deserted and returned home. The Six Nations on the Grand almost defected to the Americans and it was only the victory at Stoney Creek that changed their minds. Despite the romantic story of Laura Secord, it was the warriors of the Six Nations and the Seven Nations who won the battle of Beaver Dams when they ambushed a force sent to attack Lt. James FitzGibbon's Green 'Uns. The only part played by FitzGibbon was to bluff the Americans into believing that they were to be overwhelmed. Still, as John Norton said, the Seven Nations did all the fighting, the Six Nations got all the spoils, and FitzGibbon got the credit.

The Battle of Chippawa saw Six Nations warriors from New York fighting Six Nations warriors from the Grand River. This marked the end of the confederacy for, at the end of the war, the American Six Nations said that the Canadian Six Nations had fled from the confederacy, while the Canadians said that the confederacy had moved with them to the Grand River.  For both sides, the end of the war failed to heal the split even though both sides declared peace in 1815.