Phillipa of Clarence was born in Kent on 16 August 1355. She had another title The Countess of March. The alternative name when still referring to her was the Countess of Ulster was “Suo jure Countess of Ulster”.
Phillipa was born to Lionel of Antwerp, 1st Duke of Clarence and Elizabeth de Burgh, 4th Countess of Ulster. She was the only child to the royal couple. She was the grand daughter to Edward III. Edward III was the father to Lionel of Antwerp. Phillipa’s father, Lionel was the fifth child of Edward III.
In 1368, Phillipa married Edmund Mortimer, 3rd Earl of March in the Queen’s chapel at Reading Abbey. The alliance was considered to have consequences in English history.
The royal couple had four children. The first born was a daughter Lady Elizabeth Mortimer who was born on 12 February 1371 died 20 April 1417. She first married Sir Henry Percy and they had two children, Henry Percy, 2nd Earl of Northumberland, and Lady Elizabeth Percy. She later married Thomas de Camoys, Baron Camoys, and together they had one child, Lord Roger de Camoys.
Between the years 1377 – 1382, Phillipa was the Heiress presumptive to her first cousin Richard II. Her cousin remained childless and as a result after his death, her position as first- in- line to the throne was pushed on to her first son Roger Mortimer, 4th Earl of March.
In 1398, Phillipa’s son, Roger died in a skirmish at Kells county Meath, in Ireland and as result his son was merely six years old succeeded him to the throne. His name was Edmund Mortimer, 5th Earl of March.
However, the throne was usurped by Henry of Bolingbroke, son of John of Gaunt who is understood to be Phillipa’s first cousin.
Phillipa’s recognized seniority in the line of succession to the throne and her marriage into the Mortimer family family which was considered to be a powerful family, eventually succeded to the throne. This Edward IV succeeded her to the throne as the newly formed House of York.
On 5 January 1382, the Countess of Ulster, Phillipa of Clarence died at the age of 26. She was buried at Wigmore Abbey, Herfordshire.