Edmund de Mortimer 3d earl of March and 1st earl of Ulster

Edmund de Mortimer, 3d earl of March and 1st earl of Ulster , 1351-81, English nobleman. He succeeded (1360) his father, Roger, 2d earl of March, married (1368) Philippa, daughter of Edward III's son Lionel, duke of Clarence, and on Lionel's death (1368) inherited his estates and the title of earl of Ulster. Later the house of York (see York, house of ) traced part of its claim to the throne to this union. Mortimer held the office of marshal of England from 1369 to 1377 and supported the party that opposed John of Gaunt . After the accession of Richard II (1377) he was elected to the boy king's first council. In 1379 he was sent as lieutenant of Ireland to subdue Irish unrest. His daughter Elizabeth married Sir Henry Percy, known as Hotspur.

Mortimer, Edmund (1351–81), 3rd earl of March and 6th earl of Ulster, pre‐eminent in the 1370s because of his inheritance of the lordship of Meath and his claim to Ulster and Connacht through his wife, the heiress to Lionel of Clarence and Elizabeth de Burgh. Mortimer combined the elements sought in many appointments of chief governor during a period of weak defence and financial crisis, having both private resources to supplement his stipend and a strong personal interest in pursuing an effective military campaign. First suggested as a suitable appointee in 1373, he arrived in Ireland as lieutenant in 1379 with a large military force. He achieved some success in Ulster, Connacht, and Meath, but unrest in Leinster and Munster drew him south in 1381. His sudden death at Cork in December 1381 prompted an extreme military crisis, leaving the lordship without effective leadership. Without his personal presence, the gains made in Ulster were soon lost.

Dorothy Johnston

Mortimer, a family immensely important in later medieval Ireland. By a series of marriages they had become by 1368 theoretical lords of almost half the country. They formed the chief link between the English and Anglo‐Irish aristocracies, and often governed Ireland for the king. A Norman family who acquired Wigmore and other lands in the Welsh marches during the generations after 1066, their Irish connection began in 1247, when as one of the heirs of the Marshals they gained lands in Laois. Their active involvement dates from 1308, when Roger Mortimer, later 1st earl of March, became lord of Trim. After Roger's fall in 1330, the family suffered an eclipse until 1354. In 1368 his great‐grandson Edmund Mortimer, 3rd earl of March, married Philippa, daughter and heiress of Edward III's son Lionel of Clarence and Elizabeth de Burgh (see Burke (De Burgh)), heiress of Ulster and Connacht. Edmund was lieutenant in 1379–81, and his brother Thomas Mortimer deputy in 1382–3. Roger, the 4th earl, held the lieutenancy 1395–7 and 1397–8, his brother Edmund serving in his place during 1397. The line ended with Edmund, the 5th earl, lieutenant in 1424–5. Edmund's sister carried the Mortimer inheritance, together with a claim to the throne through Lionel, to her son Richard, duke of York, the father of Edward IV. With Edward's accession in 1461, Ulster, together with the Mortimers' other Irish estates and claims, reverted to the crown.

Robin Frame