Border Reivers were raiders along the Anglo–Scottish border from the late 13th century to the end of the 16th century. Their ranks consisted of both Scottish and English families, and they raided the entire border country without regard to their victims' nationality. Their heyday was perhaps in the last hundred years of their existence, during the Tudor dynasty in England.
If you ever had a relative that you thought had murderess tendencies -
"You might be a Border Reiver!"