Chief Massasoit was the leader of the Wampanoag Confederacy during the early 17th century, playing a crucial role in the interactions between Native Americans and European settlers, particularly the Pilgrims. He is best known for establishing a peace treaty with the Pilgrims in 1621, which allowed for a relatively cooperative relationship between the two groups. Massasoit's leadership and diplomacy were vital in ensuring the survival of the Pilgrims during their early years in New England.