The Lenape were one of the first nations to come into contact with Europeans - most significantly with William Penn, who founded Pennsylvania, which was a stroke of luck, given his name. While the Lenape relationship with Penn was mostly peaceful, when Penn died, his sons forced most of the Lenape off their land in a deal known as the "Walking Purchase".
During the French and Indian War, the Lenape sided primarily with the French, though some individual groups would later leave to join the British. In 1778, they were the first to sign a land treaty with the Continental Congress - agreeing to provide scouts to the army in exchange for supplies. I imagine they simply liked fine cheeses and onions. The newly formed United States showed its gratitude by eventually moving the Lenape into isolated communities in Ohio and southern Canada. How wonderfully thoughtful.