Edmund de Mortimer, (6 November, 1391 – 18 January, 1425), was the 5th Earl of March and Ulster. While a young child, he was briefly heir presumptive to King Richard II.

Family

Edmund was son of Roger Mortimer, 4th Earl of March by Eleanor de Holland , daughter of Thomas Holland, 2nd Earl of Kent and Alice Fitzalan . Alice was herself daughter to Richard Fitzalan, 10th Earl of Arundel and Eleanor of Lancaster.

On his father's side, he was a direct descendant of Edward III of England through Edward's second surviving son, Lionel of Antwerp. Because the senior line of succession through King Richard II had no issue, Edmund's father, Roger Mortimer, was next in line for the throne and was accordingly named heir presumptive in 1385.

Edmund was also a younger brother of Anne Mortimer, who married their cousin Richard, Earl of Cambridge, another descendant of Edward III, through a younger son, Edmund of Langley.

Heir presumptive

Edmund Mortimer's father died in Ireland on 20 July,1398. Mortimer, then seven years old, succeeded his father's title and estates and became the new heir to the throne.

On September 30, 1399 Richard was deposed and the crown usurped by Henry of Lancaster. The young earl of March and his brother Roger were then kept in custody by Henry IV, who, however, treated them honourably.

Revolt against Bolingbroke

Their captivity ended in March, 1405, when they were carried off from Windsor Castle by the opponents of the House of Lancaster. Their uncle Sir Edmund Mortimer and his brother-in-law Henry Percy (Hotspur) were leaders in league with Owen Glendower.

The boys were recaptured, and in 1409 were committed to the care of Henry of Monmouth, Prince of Wales.

Reign of Henry V

On the accession of Henry as Henry V of England, in 1413, the Earl of March was set at liberty and restored to his estates, his brother Roger having died some years previously.

He continued to enjoy the favour of the King in spite of a conspiracy in 1415 to place Mortimer on the throne, in which his brother-in-law and cousin, Richard, Earl of Cambridge, played the leading part. Mortimer was reportedly approached by the conspirators at a late stage in the preparations, and after a period of about ten days informed the King of the threat against him. Cambridge was attainted as a result and executed for treason.

Thereafter, March, along with Richard's brother Edward, Duke of York, accompanied Henry V to France in a campaign of the Hundred Years' War. When Henry V died on August 31, 1422 and was succeeded by his one-year-old son Henry VI of England, Mortimer became a member of the council of regency.

Final years

Mortimer died in Ireland in 1425, and as he left no issue the earldom of March in the house of Mortimer became extinct. The estates passed to his nephew, Anne Mortimer's son, Richard, who in 1435 was officially styled Duke of York, earl of March and Ulster, and baron of Wigmore. Richard's elder son ascended the throne in 1461 as Edward IV of England and the earldom of March became merged in the crown.