Complex sentence: His mother, Ursula Griswold, was a member of the Griswold family (of English descent) and granddaughter of Matthew Griswold, who served as the 17th Governor of Connecticut from 1784 to 1786.
Split into simpler sentences: His mother, Ursula Griswold, was a member of English descent. His maternal great-grandfather, Matthew Griswold, served as the 17th Governor of Connecticut from 1784 to 1786.