When the Europeans first arrived in what is now New York State [1], they found it inhabited by two major tribes. The Algonquins lived near the Atlantic coast and along the Hudson River Valley [2], while in upstate dwelled the five tribes of the Iroquois: the Mohawk, Oneida, Onondaga, Cayuga, and Seneca. New York then was a land of great abundance, filled with verdant forests and meadows, ice-blue rivers, lakes and streams, plump fish and game.
Around 1570, the Iroquois tribes banded together to form the Iroquois League [3], an advanced confederacy with social laws and government institutions designed to promote peace among its members. Fifty sachems, chosen from the village chiefs, governed the confederacy, and each nation had one vote. In 1722, a sixth nation, the Tuscarora, joined the Iroquois League.
Within a century after the arrival of whites, the Algonquin population was decimated, due largely to virulent European diseases such as measles and smallpox. The Iroquois, however, thrived during initial contact. First the Dutch, and then the French and British, enlisted their help in the profitable fur trade, and cultivated their friendship through gifts and the selling of firearms. During the French and Indian War, the alliance of the Iroquois with the British against the French was instrumental in allowing England to gain control over North America.
The Iroquois did not fare so well during the American Revolution. Once again allying themselves with the British, they became the object of a ruthless 1779 campaign waged by American generals Clinton and Sullivan. By the time the campaign was over, the Iroquois nation was in ruins. Thousands fled to Canada; others were resettled onto reservations.
Links:
[1] http://www.moon.com/destinations/new-york-state
[2] http://www.moon.com/destinations/new-york-state/the-hudson-valley
[3] http://www.moon.com/destinations/new-york-state/background/the-iroquois-six-nations-confederacy