Complex sentence: However, the buffer of the Susquehannock nation soon failed to protect the colony from the threat of the powerful Iroquois--the Susquehannock tribe became decimated by disease epidemic, the Susquehannock went from being a regional power to nearly extinct in the first years of the 1870s.
Split into simpler sentences: However, the buffer of the Susquehannock nation soon failed to protect the colony from the threat of the powerful Iroquois: the Susquehannock tribe became decimated by an epidemic. They went from being a regional power to nearly extinct in the first years of the 1870s.