Who is The Wampanoag ("People of the First Light") from Caleb's Crossing: A Novel and what is their importance?

"Wampanoag" is the name given to the community of natives living near the white community where Bethia and her family make their home (Great Harbor). The community has a fairly good relationship with the white people of the area, in spite of the attitudes and actions of Tequamuck and because of the determined efforts of Pastor Mayfield.