The tribes were highly decentralized and bands operated independently, establishing territory in different geographic areas. European colonization European colonization of the region began in the 1620s, with Dutch colonists congregating around the lower Hudson and western Long Island. The Dutch attempted to establish jurisdiction from New Amsterdam over the western portion of Long Island (including what are now the New York City boroughs of Brooklyn and Queens). The eastern part of Long Island was colonized by English settlers of the New England Confederation. Settlers from southern New England began to migrate to Long Island's north shore in the early eighteenth century. Indigenous populations declined significantly within a few decades of European contact, due to new infectious diseases to which they had no acquired immunity. This separation between zones of Dutch and English influence was formalized in their Treaty of Hartford in 1650, which set a border running south from Oyster Bay. The Native Americans on Long Island played an important role in the trade economy; they fashioned shells harvested there into small beads to create sewant, or wampum (wampompeag in Lenape- a term later shortened by the English). These were used to decorate ceremonial wear and were the most highly prized. Displacement The Pequot War (1634–1638) in southern New England and Kieft's War (1643–1645) in the New York metropolitan area were two major conflicts between the indigenous peoples and the colonists. Exposure to new Eurasian infectious diseases, such as measles and smallpox, dramatically reduced the numbers of Native Americans on Long Island. In addition, some Native American settlements on Long Island migrated away under pressure from European encroachment. By 1659, their population was reduced to less than 500. After the American Revolutionary War, their numbers were reduced to 162 people by 1788. By this time, Samson Occom had persuaded many survivors to join the Brothertown Indians in western upstate New York, where the Oneida people of the Iroquois Confederacy shared their reservation for several years. Exonyms For generations, colonists mistakenly used the place names as exonyms for peoples, thinking they referred to distinct tribes. Among the many locations on Long Island used by the native peoples, 19th-century American publications erroneously identified the following thirteen as "tribes" on Long Island: Metoac was a term erroneously used by amateur anthropologist and U.S. Congressman Silas Wood to describe Lenape and Pequot Native Americans on Long Island in New York state, in the belief