Complex sentence: However, in 1887, some former scouts were involved in the brief Crow War during which the United States Army fought a successful battle against hostile Crows just north of the Little Bighorn battlefield.
Split into simpler sentences: However, in 1887, some former scouts were involved in the brief Crow War. During which the United States Army fought a successful battle against hosltile Crows just north of the Little Bighorn battlefield.