The Dakota initially tolerated the French partnership with the Ojibwe because their longtime enemies served as an intermediary, bringing valuable French goods to the Dakota. After the increasingly expansionist French moved into Minnesota permanently and fostered alliances with (and supplied weapons to) the Cree and Assiniboine to the north, also both enemies of the Dakota, the Dakota attacked Fort St. Charles in 1736.

The Ojibwe decided to cement their relationship with the French, increase their territory, and settle old scores by attacking the Dakota. Allied with the Cree and Assiniboine and supplied with firearms and military advice by the French, the highly motivated Ojibwe slowly swept across Dakota territory in Minnesota, Wisconsin, and Canada.

At the bloody, three-day Battle of Kathio (about 1750), the Ojibwe routed the Dakota in their spiritual and political heart on the western shore of Mille Lacs. Though this was the decisive clash (that is, assuming it really happened; some historians doubt it), the war continued, and so did the Dakota exodus to the south and west.

By 1780 the Dakota had been pushed completely south of the Minnesota River, where these forest-dwellers had to adapt their lifestyle to the prairies.

The French and British were at each other’s throats again by 1754. The French and Indian War, the North American campaign that led to the Seven Years’ War in Europe (1756–1763), began with the British, led by a 23-year-old George Washington, trying to evict the French from western Pennsylvania. The British trounced the French on both continents in this, the last of four major conflicts between the colonial powers during the previous 75 years, and took Canada and all French territories east of the Mississippi. Spain had received all French land west of the Mississippi a year earlier in a scheme to keep it out of British hands.