How did the Revolution split the Haudenosaunee, and what did Sullivan's 1779 campaign do?

Each nation made its own choice, and they chose differently. Both British officials and the Continental Congress sought the allegiance, or at least the neutrality, of the Haudenosaunee, also known as the Six Nations. They divided. Most Senecas, Cayugas, Onondagas and Mohawks allied with the British, while most Oneidas and Tuscaroras joined the Americans.

The division was visible on the field. In Oneida oral history, a prominent Oneida woman named Polly Cooper brought hundreds of bushels of white corn to hungry American troops and taught them how to prepare it safely. Elsewhere, Loyalists and their Haudenosaunee allies raided American frontier settlements and even the villages of the Oneida, and at Cherry Valley in 1778 Seneca warriors killed 16 soldiers and 32 civilians, mostly women and children.

In 1779 Washington ordered a campaign under General John Sullivan in response to raids on frontier settlements, with the stated aim of "the total destruction and devastation of their settlements." The expedition razed 40 villages and destroyed crops and food stores, driving just over 5,000 people to Fort Niagara to seek British protection. How many died is debated: one historian estimates around 200 killed in the fighting and as many as 1,000 later dying in refugee camps, while another estimated several hundred deaths that winter. Some scholars call the campaign a genocide, although the term is disputed.

It did not end the fighting, and the peace did not protect them. The campaign triggered devastating revenge attacks. And in the 1783 Treaty of Paris negotiations the Haudenosaunee were ignored, and later treaties led them to cede most of their traditional territory.