In the late eighteenth century,the tension between England and the American colonies became too great to bear.In 1776,150years after the pilgrims had landed at plymouth,the colonists signed the Declaration of Independence.This act officially declared their separation from England.The war for independence ended five years later with the defeat of Cornwallis's British troops at yorktown,Virginia.The adoption of the United states Constitution followed about seven years thereafter and laid the groundwork for the new nation's goverment.