ortimer, Roger, First Earl of March (?1287-1330). The mis-government of the country under Edward II gave his wife Isabella the excuse for allying herself with Mortimer, and together they invaded England from the Low Countries in 1326. During the minority of Edward III Mortimer and his royal paramour Isabella ruled the country although there was nominally a council of regency; but in 1330 the young king asserted himself, and had Mortimer put to death. [The Home University Encyclopedia, 1946]