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. "Reive" is an early English word for "to rob", from the Northumbrian and Scots Inglis verb reifen from the Old English rēafian, and thus related to the archaic Standard English verb reave ("to plunder", "to rob").
England and Scotland were frequently at war during the late Middle Ages. During these wars, the livelihood of the people on the borders was devastated by the contending armies. Even when the countries were not at war, tension remained high, and royal authority in one or the other kingdom was often weak. The uncertainty of existence meant that communities or peoples kindred to each other would seek security through their own strength and cunning, and improve their livelihoods at their nominal enemies' expense. Loyalty to a feeble or distant monarch and reliance on the effectiveness of the law usually made people a target for depredations rather than conferring any security.