 Before the arrival of British colonists, the area that is now southern Berkshire County, Massachusetts was inhabited by communities of the Mahican tribal confederation.The population of these communities changed over the 17th century as war (sometimes with European settlers and sometimes with the neighboring Iroquois), disease, and migration made them smaller and more diverse.By the 1720s they had sold off most of their tribal lands, and lived in relative peace in two remaining tracts of land on the Housatonic River.