Edmund de Mortimer, 3rd Earl of March and jure uxoris Earl of Ulster, is killed at Cork on December 27, 1381. His sudden death leaves the colony without effective leadership and prompts a military crisis.

Mortimer, the son of Roger Mortimer, 2nd Earl of March, by his wife Philippa, daughter of William Montagu, 1st Earl of Salisbury and Catherine Grandison, is born on February 1, 1352. An infant at the death of his father, as a ward of the crown he is placed by Edward III of England under the care of William of Wykeham and Richard FitzAlan, 3rd Earl of Arundel. The position of the young earl, powerful on account of his possessions and hereditary influence in the Welsh marches, is rendered still more important by his marriage on August 24, 1369 at the age of 17 to the 14-year-old Philippa, the only child of the late Lionel of Antwerp, 1st Duke of Clarence, the second son of Edward III.

Lionel’s late wife, Elizabeth, had been daughter and heiress of William Donn de Burgh, 3rd Earl of Ulster, and Lionel had himself been created Earl of Ulster before his marriage. Mortimer inherits the title Earl of Ulster on Lionel’s death. Therefore, the Earl of March not only represents one of the chief Anglo-Norman lordships in Ireland in right of his wife Philippa, but Philippa’s line is also the second most senior line of descent in the succession to the crown, after Edward the Black Prince and his son, King Richard II of England. John of Gaunt, younger brother of Prince Edward, had become the 1st Duke of Lancaster and thus the source of the House of Lancaster‘s claim to the throne.

This marriage has, therefore, far-reaching consequences in English history, ultimately giving rise to the claim of the House of York to the crown of England contested in the Wars of the Roses between the Yorks and the Lancasters; Edward IV being descended from the second adult son of Edward III as great-great-grandson of Philippa, countess of March, and in the male line from Edmund of Langley, 1st Duke of York and the fourth adult son of Edward III. Mortimer’s son, Roger Mortimer, 4th Earl of March, becomes heir presumptive to the English crown during the reign of Richard II.

Mortimer, now styled Earl of March and Ulster, becomes Earl Marshal of England in 1369, and is employed in various diplomatic missions during the following years. He is a member of the committee appointed by the Peers to confer with the Commons in 1373, the first instance of such a joint conference since the institution of representative parliaments on the question of granting supplies for John of Gaunt’s war in France.

Mortimer participates in the opposition to Edward III and the court party, which grows in strength towards the end of the reign, taking the popular side and being prominent in the Good Parliament of 1376 among the lords who support the Prince of Wales and oppose the Court Party and John of Gaunt. The Speaker of the House of Commons in this parliament is Mortimer’s steward, Peter de la Mare, who firmly withstands John of Gaunt in stating the grievances of the Commons, in supporting the impeachment of several high court officials, and in procuring the banishment of the king’s mistress, Alice Perrers. Mortimer is a member of the administrative council appointed by the same parliament after the death of Edward, the Black Prince, to attend the king and advise him in all public affairs.

Following the end of the Good Parliament its acts are reversed by John of Gaunt, Mortimer’s steward is jailed, and he himself is ordered to inspect Calais and other remote royal castles as part of his duty as Marshal of England. He instead chooses to resign the post.

On the accession of Richard II in 1377, Mortimer becomes a member of the standing council of government; though as husband of the heir-presumptive to the crown he wisely refrains from claiming any actual administrative office. The richest and most powerful person in the realm is, however, the king’s uncle John of Gaunt, whose jealousy leads Mortimer to accept the office of Lord Lieutenant of Ireland in 1379. He succeeds in asserting his authority in eastern Ulster, but fails to subdue the O’Neill dynasty farther west. Proceeding to Munster to put down the turbulent southern chieftains, he is killed at Cork on December 27, 1381. He is buried in Wigmore Abbey, of which he had been a benefactor, and where his wife Philippa is also interred.

(Pictured: Coat of Arms of the House of Mortimer)