The relationship between the Lenape and the Settlers changed after William Penn returned to England, leaving a land agent in charge of Pennsylvania. In 1737, the Agent set about to swindle the Lenape out of 1.2 million acres of land through the infamous Walking Purchase--setting into motion 20 years of violence in the region between the Lenape and the colonial settlers.
More about the Walking Purchase
In 1758, the Lenape and 12 other Native American Nations signed the Treaty of Easton with the British. In exchange for the right to lands to the west of the Susquehanna River, these Nations agreed to fight for the British against the French in the war over the American colonies.
Over a period of 250 years many of the Lenape people were removed and dispersed throughout the country as treaties were made and broken repeatedly. Some took refuge with other tribes in the west. Other families remained and are known today as the Lenape Nation of Pennsylvania.