Several members of the Mortimer family were summoned to Parliament during the reign of Edward I, thereby making them hereditary barons in the Peerage of England. The most important family with this surname were the lords of Wigmore, a marcher lordship on the borders of Herefordshire and Shropshire with Wales, living at Wigmore Castle. The second Baron Mortimer of Wigmore was created Earl of March. The others probably all belonged to juvenile branches of that family.