Roger Mortimer , 4th Earl of March Roger de Mortimer , 4th Earl of March and 6th Earl of Ulster ( 11 April 1374 – 20 July 1398 ) was considered the heir presumptive to King Richard II . Roger Mortimer , born 11 April 1374 at Usk in Monmouthshire , was the eldest son of Edmund Mortimer , 3rd Earl of March , by his wife Philippa Plantagenet , who as the daughter of Lionel of Antwerp , 1st Duke of Clarence , and granddaughter of King Edward III , had a claim to the crown which she passed on to her children . He had a younger brother , Edmund Mortimer , and two sisters , Elizabeth , who married Henry ' Hotspur ' Percy , and Philippa ( 1375 - 1401 ) , who married firstly John Hastings , 3rd Earl of Pembroke ( d . 1389 ) , killed in a tournament at Woodstock Palace , secondly Richard de Arundel , 11th Earl of Arundel ( 1346 - 1397 ) , beheaded in 1397 , and thirdly , Sir Thomas Poynings . Roger Mortimer ' s mother , Philippa , died on or before 7 January 1378 , and was buried at Wigmore Abbey . His father , said to have caught cold crossing a river in winter , died at the Dominican friary at Cork in Munster on 27 December 1381 , leaving his son to succeed to a title and extensive estates at only six years of age . According to Davies , the wardship of such an important heir was an ' issue of political moment in the years 1382 – 4 ' . Eventually , on 16 December 1383 , Mortimer ' s estates in England and Wales were granted for £4000 per annum to a consortium consisting of Mortimer himself , the Earls of Arundel , Northumberland , and Warwick , and John , Lord Neville . The guardianship of Mortimer ' s person was initially granted to Arundel , but at the behest of King Richard ' s mother , Joan of Kent , in August 1384 Mortimer ' s wardship and marriage were granted , for 6000 marks , to Joan ' s son , Thomas Holland , 2nd Earl of Kent , who has Richard ' s half - brother , and on or about 7 October 1388 . Mortimer married Kent ' s daughter , Eleanor Holland , who was Richard ' s half - niece . Mortimer did homage and was granted livery of his lands in Ireland on 18 June 1393 , and of those in England and Wales on 25 February 1394 . King Richard had no issue , and Mortimer , a lineal descendant of Edward III , was next in line to the throne and married to his half - niece . Cokayne states that in October 1385 Mortimer was proclaimed by the King as heir presumptive to the crown . However according to Davies the story that Richard publicly proclaimed Mortimer as heir presumptive in Parliament in October 1385 is baseless , although contemporary records indicate that his claim was openly discussed at the time . He was knighted by the King on 23 April 1390 . Career . After he came of age , Mortimer spent much of his time in Ireland . King Richard had first made Mortimer his Lord Lieutenant of Ireland on 24 January 1382 when he was a child of seven , with his uncle , Sir Thomas Mortimer ( d . before 14 March 1403 ) , acting as his deputy . The King reappointed Roger Mortimer as his lieutenant In Ireland on 23 July 1392 , and in September 1394 Mortimer accompanied the King on an Irish expedition . On 25 April 1396 the King appointed him lieutenant in Ulster , Connacht , and Meath , and Mortimer was in Ireland for most of the following three years . In April 1397 the King reappointed him lieutenant for a further three years . Mortimer ' s residence in Ireland ensured that his political role in England was a minor one . His closest relationships in England appear to have been with family members , including his brother , Edmund , to whom he granted lands and annuities ; the Percy family , into which his elder sister , Elizabeth had married ; and the Earl of Arundel , who had married his younger sister , Philippa . As Davies points out , Mortimer ' s ' wealth and lineage meant that , sooner or later , he would be caught up in the political turmoil of Richard II ' s last years ' . On 4 September 1397 he was ordered to arrest his uncle , Sir Thomas Mortimer ( d . before 14 March 1403 ) for treason regarding his actions at the Battle of Radcot Bridge , but made no real attempt to do so . Even more inauspiciously , when summoned to a Parliament at Shrewsbury in January 1398 , he was ' rapturously received ' , according to Adam Usk and the Wigmore chronicler , by a vast crowd of supporters wearing his colours . These events excited the King ' s suspicions , and on Mortimer ' s return to Ireland after the Parliament in January 1398 , ' his enemy , the Duke of Surrey , his brother - in - law , was ordered to follow and capture him ' . On 20 July 1398 , at the age of 24 , Mortimer was slain in a skirmish with ' O ' Brien ' s men ' at Kells . The Wigmore chronicler says that he was riding in front of his army , unattended and wearing Irish garb , and that those who slew him did not know who he was . He was interred at Wigmore Abbey . The King went to Ireland in the following year to avenge Mortimer ' s death . Mortimer ' s young son , Edmund Mortimer , 5th Earl of March , succeeded him in the title and claim to the throne . The Wigmore chronicler , while criticizing Mortimer for lust and remissness in his duty to God , extols him as ' of approved honesty , active in knightly exercises , glorious in pleasantry , affable and merry in conversation , excelling his contemporaries in beauty of appearance , sumptuous in his feasting , and liberal in his gifts ' . Marriage and children . By his wife Eleanor he had two sons and two daughters : In June 1399 Roger Mortimer ' s widow , Eleanor , married Edward Charleton , 5th Baron Cherleton , by whom she had two daughters : Eleanor died 6 or 18 October 1405 .