Dutch and English sailors, fishermen, and adventurers began visiting New England. The first permanent settlements in the region did not begin until after the settling of Plymouth Colony in 1620. These early seafarers introduced several infectious diseases to which the Native Americans had no prior exposure, resulting in epidemics with mortality rates as high as 90%. Smallpox killed many of the Native Americans from 1617–1619, 1633, 1648–1649 and 1666. Similarly influenza, typhus, and measles also afflicted the Native Americans throughout the period.