|Lady Elizabeth Mortimer|
The tomb at St. George's Church, Trotton of Elizabeth and her husband, Thomas de Camoys
|Spouse(s)||Henry 'Hotspur' Percy
Thomas de Camoys, 1st Baron Camoys
Sir Roger Camoys
|Father||Edmund Mortimer, 3rd Earl of March|
|Mother||Philippa Plantagenet, 5th Countess of Ulster|
|Born||12 February 1371
Usk, Monmouthshire, Wales
|Died||20 April 1417
Elizabeth Mortimer, Baroness Camoys (12 February 1371 – 20 April 1417) was an English noblewoman, who, as the granddaughter of Lionel of Antwerp, 1st Duke of Clarence, and great-granddaughter of King Edward III, was in the line of succession to the English crown. Her first husband was Sir Henry Percy, known to history as 'Hotspur'. She married secondly Thomas de Camoys, 1st Baron Camoys. She is represented as 'Kate, Lady Percy,' in Shakespeare's Henry IV, Part 1, and briefly again as 'Widow Percy' in Henry IV, Part 2.
Claim to the English throne 
Elizabeth Mortimer was born at Usk, Monmouthshire, Wales on 12 or 13 February 1371, the eldest daughter of Edmund Mortimer, 3rd Earl of March, and his wife, Philippa, the only child of Lionel, 1st Duke of Clarence, and Elizabeth de Burgh, Countess of Ulster. Elizabeth Mortimer had two brothers, Sir Roger (1374-1398) and Sir Edmund (1376-1409), and a younger sister, Philippa (1375-1401), who married firstly John Hastings, 3rd Earl of Pembroke (d.1389), secondly Richard de Arundel, 11th Earl of Arundel (1346-1397), and thirdly, Sir Thomas Poynings.
Lionel, Duke of Clarence, was the second surviving son of King Edward III, and his Mortimer grandchildren were thus in the line of succession to the English crown. While it is often said that Richard II publicly proclaimed Elizabeth Mortimer's brother, Roger Mortimor, as his heir presumptive in Parliament in October 1385, according to Davies the story is without foundation, although contemporary records do indicate that Roger Mortimer's claim to the throne was openly discussed.
Marriages and issue 
Before 10 December 1379, when she was still only a child, she was married to her first husband, Henry Percy (1364-1403), eldest son of Henry Percy, 1st Earl of Northumberland. He was seven years her senior, and would later acquire a reputation as a great soldier and warrior, known to history as 'Hotspur'. The couple resided at Alnwick Castle in Northumberland. They had two children:
- Henry Percy, 2nd Earl of Northumberland (3 February 1393- 22 May 1455), who married Eleanor Neville, by whom he had issue. He was slain at the First Battle of St Albans.
- Lady Elizabeth Percy (c.1395-26 October 1436), who married firstly John Clifford, 7th Baron de Clifford, slain at the Siege of Meaux on 13 March 1422, by whom she had issue, and secondly Ralph Neville, 2nd Earl of Westmorland (d. 3 November 1484), by whom she had a son, Sir John Neville.
On 21 July 1403 Elizabeth Mortimer's first husband, Henry Percy, was slain at the Battle of Shrewsbury while commanding the rebel army which fought against the superior forces of King Henry IV. He was buried in Whitchurch, Shropshire; however when rumours circulated that he was still alive, 'Henry IV had the corpse exhumed and displayed it, propped upright between two millstones, in the market place at Shrewsbury'. This done, the King dispatched Percy's head to York, where it was impaled on one of the city's gates; his four quarters were first sent to London, Newcastle upon Tyne, Bristol, and Chester before they were finally delivered to Elizabeth. She had him buried in York Minster in November of that year. In January 1404, Percy was posthumously declared a traitor and his lands were forfeited to the Crown. The King ordered Elizabeth herself arrested on 8 October 1403.
Sometime after 3 June 1406 Elizabeth Mortimer married her second husband, Thomas de Camoys, 1st Baron Camoys, by whom she had a son, Sir Roger Camoys. Like her first husband, Camoys was a renowned soldier who commanded the rearguard of the English army at the Battle of Agincourt on 25 October 1415.
Elizabeth died on 20 April 1417 at the age of 46 years. She was buried in St. George's Church at Trotton, Sussex. Her second husband was buried beside her. Their table-tomb with its fine monumental brass depicting the couple slightly less than life size and holding hands can be viewed in the middle of the chancel inside the church.
In fiction 
Lady Elizabeth is represented as Kate, Lady Percy in William Shakespeare's play Henry IV, Part 1. 
- Cokayne 1932, p. 448; Richardson II 2011, pp. 190-1; Richardson III 2011, pp. 193-5, 307, 335, 341; Holmes 2004; Tout 2004.
- Davies 2004.
- Richardson III 2011, p. 341.
- Richardson III 2011, pp. 343-4.
- Richardson I 2011, p. 507; Richardson III 2011, p. 250.
- Richardson III 2011, p. 341.
- Walker 2004.
- Cokayne 1936, p. 714.
- Richardson III 2011, p. 341.
- Cokayne 1912, p. 508; Richardson I 2011, pp. 398-9.
- Leland 2004.
- Richardson III 2011, p. 342.
- "Lady Kate Percy character analysis". Shmoop.
- Cokayne, George Edward (1912). The Complete Peerage, edited by H.A. Doubleday II. London: St. Catherine Press. pp. 506–10.
- Cokayne, George Edward (1932). The Complete Peerage, edited by H.A. Doubleday VIII. London: St. Catherine Press. pp. 445–53.
- Cokayne, George Edward (1936). The Complete Peerage, edited by H.A. Doubleday IX. London: St. Catherine Press. pp. 713–14.
- Davies, R.R. (2004). Mortimer, Roger (VII), fourth earl of March and sixth earl of Ulster (1374-1398). Oxford Dictionary of National Biography. Retrieved 28 September 2012.
- Holmes, George (2004). Mortimer, Edmund (III), third earl of March and earl of Ulster (1352-1381). Oxford Dictionary of National Biography. Retrieved 29 September 2012.
- Leland, John L. (2004). Camoys, Thomas, Baron Camoys (c.1350-1420/21). Oxford Dictionary of National Biography. Retrieved 26 September 2012.
- Richardson, Douglas (2011). Magna Carta Ancestry: A Study in Colonial and Medieval Families, ed. Kimball G. Everingham I (2nd ed.). Salt Lake City. ISBN 1449966373
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- Richardson, Douglas (2011). Magna Carta Ancestry: A Study in Colonial and Medieval Families, ed. Kimball G. Everingham III (2nd ed.). Salt Lake City. ISBN 144996639X
- Tout, T.F., rev. R.R. Davies (2004). Mortimer, Sir Edmund (IV) (1376-1408/9). Oxford Dictionary of National Biography. Retrieved 29 September 2012.
- Walker, Simon (2004). Percy, Sir Henry (1364-1403). Oxford Dictionary of National Biography. Retrieved 29 September 2012.
- Cawley, Charles, Medieval Lands, Earls of March