General Washington gave command to John Sullivan in 1779 to outfit and lead an expedition into the Seneca-Cayuga homeland.  It will be a scorched earth campaign that will leave almost the entire population of both the Seneca and Cayuga Nations homeless. Destitute of any food or clothing thousands will head to Fort Niagara for shelter.  

Sources:

Forgotten Allies: The Oneida Indians and the American Revolution by Joseph T. Glatthaar and James Kirby Martin

The Papers of General George Washington

Joseph Brant, 1743-1807, Man of Two Worlds By Isabel Thompson Kelsay

Journal of General John Sullivan