By the late 18th century with the French governmental influence gone from Canada Iroquois power had weakened, relative to the steady growth in European-Americans' populations, and internal strife eroded the political unity of the Iroquois Confederacy as they faced pressures from colonists itching to move west and a desire to keep them out of Amerindian lands. During the American Revolutionary War, some Iroquois sided with the British and some with the Americans, resulting in civil war among the Iroquois. In the late 1770s, British-allied Iroquois attacked various American frontier settlements, prompting counter-attacks, culminating in the Sullivan Expedition of 1779, which destroyed most of the Iroquois towns and effectively broke Iroquois power. After the Revolutionary War, the Iroquois and other Indians of the region were assigned reservations. Most of their land, including the Finger Lakes region, was opened up to purchase and settlement.