Roger Mortimer (or Roger de Mortimer) was the name of several Marcher lords, members of a powerful Norman family living on the borders of England and Wales in the 13th and 14th centuries. They intermarried with the local Welsh nobility, gradually becoming Welsh by adoption.

Roger Mortimer (1231-1282), 1st Baron Wigmore, was the son of Ralph de Mortimer and his wife, Gwladus Ddu - daughter of Llywelyn the Great. He married into another Marcher family, that of de Braose. He was at times an enemy, at times an ally, of Llywelyn the Last, and it was as a result of his double-dealing that Llywelyn was lured into the ambush that killed him.

Roger Mortimer (~1256-1326), son of the above, was Justice of Wales under King Edward II of England. His opposition to Hugh le Despenser led to his capture and imprisonment in the Tower of London, where he died.

Roger Mortimer (1287-1330), nephew of the above and grandson of the 1st Baron Wigmore, was the best-known of his name, but not on merit. As a result of his adulterous relationship with Edward II's queen, Isabella of France, he became effective ruler of England after Edward had been disposed of.

Since he was an infant at the death of his father, Edmund, he was placed by Edward I under the guardianship of Piers Gaveston, and was knighted by Edward in 1306; Mortimer's mother being a relative of Edward's consort, Eleanor of Castile. Through his marriage with Joan de Join-ville, or Genevill, Roger not only acquired increased possessions on the Welsh marches, including the important castle of Ludlow, which became the chief stronghold of the Mortimers, but also extensive estates and influence in Ireland, whither he went in 1308 to enforce his authority. This brought him into conflict with the De Lacys, who turned for support to Edward Bruce, brother of Robert Bruce, king of Scotland. Mortimer was appointed lord-lieutenant of Ireland by Edward II. in 1316, and at the head of a large army drove Bruce to Carrickfergus, and the De Lacys into Connaught, wreaking vengeance on their adherents whenever they were to be found.

He was then occupied for some years with baronial disputes on the Welsh border until about 1318, when he began to interest himself in the growing opposition to Edward II. and his favourites, the Despensers; and he supported Humphrey de Bohun, earl of Hereford, in refusing to obey the king’s summons to appear before him in 1321.

Forced to surrender to the king at Shrewsbury in January 1322, Mortimer was consigned to the Tower of London, whence he escaped to France in August 1324. In the following year Isabella, wife of Edward II, anxious to escape from her husband, obtained his consent to her going to France to use her influence with her brother, Charles IV, in favour of peace. At the French court the queen found Roger Mortimer; she became his mistress soon afterwards, and at his instigation refused to return to England so long as the Despensers retained power as the king’s favourites.

The scandal of Isabella’s relations with Mortimer compelled them both to withdraw from the French court to Flanders, where they obtained assistance for an invasion of England. Landing in England in September 1326, they were joined by Henry, Earl of Lancaster; London rose in support of the queen; and Edward took flight to the west, whither he was pursued by Mortimer and Isabella.

After wandering helplessly for some weeks in Wales, the king was taken on the 16th of November, and was compelled to abdicate in favour of his son. But though the latter was crowned as Edward III in January 1327, the country was ruled by Mortimer and Isabella, who procured the murder of Edward II in the following September.

Rich estates and offices of profit and power were now heaped on Mortimer, and in September 1328 he was created Earl of March. Greedy and grasping, he was no more competent than the Despensers to conduct the government of the country. The jealousy and anger of Lancaster having been excited by March’s arrogance, Lancaster prevailed upon the young king, Edward III, to throw off the yoke of his mother’s paramour. At a parliament held at Nottingham in October 1330 a plot was successfully carried out by which March was arrested in the castle, and, in spite of Isabella’s entreaty to her son to “have pity on the gentle Mortimer,” was conveyed to the Tower. Accused of assuming royal power and of various other high misdemeanours, he was condemned without trial and hanged at Tyburn on the 29th of November 1330, his vast estates being forfeited to the crown. March’s wife, by whom he had four sons and eleven daughters, survived till 1356. The daughters all married into powerful families, chiefly of Marcher houses. His eldest son, Edmund, was father of Roger Mortimer, who was restored to his grandfather’s title as 2nd earl of March.

Roger Mortimer (~1327-1360), grandson of the above, was knighted by Edward III, and recovered his family inheritance, becoming the 2nd Earl of March after having loyally served Edward, the Black Prince.

Roger Mortimer (1374-1398), 4th Earl of March and Ulster, was the son of the 3rd earl, and was descended through his mother from King Edward III, and for this reason was named by the childless King Richard II of England as his heir. He held enormous estates in Wales, but was killed at the Battle of Kells. He was the father of Anne Mortimer and Edmund Mortimer, 5th Earl of March.

He succeeded to the titles and estates of his family when a child of seven, and a month afterwards he was appointed lord-lieutenant of Ireland, his uncle Sir Thomas Mortimer acting as his deputy. Being a ward of the Crown, his guardian was the earl of Kent, half-brother to Richard II; and in 1388 he married Kent’s daughter, Eleanor. The importance which he owed to his hereditary influence and possessions, and especially to his descent from Edward III, was immensely increased when Richard II publicly acknowledged him as heir presumptive to the crown in 1385. In 1394 he accompanied Richard to Ireland, but notwithstanding a commission from the king as lieutenant of the districts over which he exercised nominal authority by hereditary right, he made little headway against the native Irish chieftains. March enjoyed great popularity in England though he took no active part in opposing the despotic measures of the king; in Ireland he illegally assumed the native Irish costume. In August 1398 he was killed in fight with an Irish clan, and was buried in Wigmore Abbey.