Moving to a free state allowed the Stones to emancipate them .
His mother - in - law 's will bequeathed the slaves to his wife and her children in perpetuity in a way that placed them under the control of trustees .
Moving to a free state allowed the Stones to emancipate slaves .
His mother - in - law 's will bequeathed the slaves to his wife and her children in perpetuity in a way that placed them under the control of trustees .