Proslavery raiders from Missouri who entered the Kansas Territory from 1854 to 1858 to try to ensure Kansas would enter the US as a slave state. They were opposed by [[Abolitionist|Abolitionists]] from the North, many of whom had been sponsored by the [[New England Emigrant Aid Society]]. The leaders of the Border Ruffians were [[B.F. Stringfellow]] and [[David R. Atchison]]. Both sides used terrorist tactics in a conflict that became known as [[Bleeding Kansas]].