Complex sentence: Documentation of his life in numerous sources enable the tribe to achieve state recognition in the 2ist century, because records showed he identified as Indian-a continuity of cultural and ethnic identity after the American Revolutionary War and through times of change.
Split into simpler sentences: Documentation of his life in numerous sources enabled the tribe to achieve state recognition in the 2ist century, because records showed he identified as Indian. This provided proof that the people had a continuity of cultural and ethnic identity after the American Revolutionary War and through times of change.