In the 17th century the Pequot tribe, rival of the Narragansett, was centered along the Thames River in present-day southeast Connecticut. As the colonists expanded westward, friction began to develop. Points of tension included unfair trading, the sale of alcohol, destruction of Pequot crops by colonial cattle and competition over hunting grounds.

Further poisoning the relationship was the disdain in which the Indians were held by the colonists; many felt no qualms about dispossessing or killing those whom they regarded as ungodly savages.

In July 1636, John Oldham, a trader of questionable honesty, was killed by the Pequot. The incident led Gov. John Endicott to call up the militia. What followed was the first significant clash between English colonists and North American Natives. Allying themselves with the Mohegan and Narragansett, the colonists attacked a Pequot village on the Mystic River (near present-day New London) in May 1637. Encircling their foes under the cover of night, the colonists set the Indian dwellings ablaze, then shot the natives as they fled from their homes. From 400 to 700 Indian men, women and children were killed; many of the survivors were sold into slavery in Bermuda. The Pequot chieftain Sassacus was captured by the Mohawks and executed. His tribe was virtually exterminated.

The colonists and their allies set an infortunate precedent in the Pequot War by ignoring the conventions of European warfare to punitively devastate the homes and lives of men, women and children.