Complex sentence: The Dutch and native Siwanoy were engaged in Kieft's War during the family's tenure there, and in August 1643 the household was attacked by the natives, and all members of the family were killed, except for nine-year old Hutchinson.
Split into simpler sentences: The Dutch and native Siwanoy were engaged in Kieft's War during the family's tenure there. In August 1643 Siwonoy attacked the emigrant household, and killed all members of the family, except for nine-year old Hutchinson.