Complex sentence: Because European Americans used many different names for the Cheyenne, the military did not realized the extent of their unification, but destroyed seven camps of theirs before 1876, more than any other tribe suffered.
Split into simpler sentences: Because European Americans used many different names for the Cheyenne, the military did not realize the extent of their unification. Nonetheless, the US Army destroyed seven camps of theirs before 1876, more than any other tribe suffered.