Marcher lord
A marcher lord (Welsh: barwn y mers) was a noble appointed by the king of England to guard the border (known as the Welsh Marches) between England and Wales. A marcher lord was the English equivalent of a margrave (in the Holy Roman Empire) or a marquis (in France) before the introduction of the title of "marquess" in Britain; no marcher lord ever bore the rank of marquess.