Roger de Mortimer, 4th Earl of March and 6th Earl of Ulster (grandson of Lionel of Antwerp, 1st Duke of Clarence), had in 1385 been publicly acknowledged as heir presumptive to the English crown.

He had accompanied Richard II to Ireland in 1394 but, notwithstanding a commission from the king as lieutenant of the districts over which he exercised nominal authority by hereditary right, he had made little headway against the native Irish chieftains.

The following year Mortimer had nevertheless, been given broader authority as lieutenant of Ireland.

March enjoys great popularity in England though he has taken no active part in opposing the despotic measures of the King.

He is killed on July 20, 1398, at the Battle of Kells, a border town of the Pale, in a fight with an Irish clan, and is buried in Wigmore Abbey in Hereford, his titles and the designation of heir presumptive passing to his young son, Edmund Mortimer, 5th Earl of March.