Complex sentence: Pequot numbers grew appreciably--the Mashantucket Pequot especially--during the 1970s and 1980s when tribal chairman Richard A. Hayward persuaded Pequot to return to their tribal homeland.
Split into simpler sentences: Pequot numbers grew appreciably--the Mashantucket Pequot especially--during the 1970s and 1980s. The tribal chairman Richard A. Hayward encouraged the Pequot to return to their tribal homeland.