On 23 Dec 1392 [his mother-in-law] Isabella of Castile Duchess York (age 37) died. She was buried at King's Langley Priory, Hertfordshire [Map]. She the wife of [his father-in-law] Edmund of Langley 1st Duke of York (age 51). Isabella had travelled to England with her sister Constance of Castile Duchess of Lancaster (age 38) who had married Edmund's elder brother John of Gaunt 1st Duke Lancaster (age 52). Isabella and Edmund's marriage was not, apparently, a happy one. She is known to have had an affair with John Holland 1st Duke Exeter (age 40) who may have been the father of [his brother-in-law] Richard of Conisbrough 1st Earl Cambridge (age 7) progenitor of the House of York.

On 17 Dec 1399 the conspirators met at Abbey House Westminster Abbey [Map] including Thomas Blount (age 47), Thomas Despencer 1st Earl Gloucester (age 26), Thomas Holland 1st Duke Surrey (age 25), John Holland 1st Duke Exeter (age 47), Ralph Lumley 1st Baron Lumley (age 39), John Montagu 3rd Earl Salisbury (age 49), [his brother-in-law] Edward 2nd Duke of York 1st Duke Albemarle (age 26), Bernard Brocas (age 45). They plotted to capture King Henry IV of England (age 32) at a Tournament in Windsor, Berkshire [Map] on the Feast of Epiphany hence the Epiphany Rising.

After 07 Jan 1400. Henry IV's (age 32) Parliament. 2.30. Also, be it remembered that whereas Thomas Holland, formerly earl of Kent (deceased), John Holland, formerly earl of Huntingdon (age 48), John Montague, formerly earl of Salisbury (deceased), Thomas, formerly Lord Despenser (age 26), and Ralph Lumley (deceased), knight, recently rose up in various parts of England and rode in warlike manner, treacherously, against our lord the king, contrary to their allegiance, to destroy our said lord the king and other great men of the realm, and to populate the said realm with people of another tongue, they were seized and beheaded in their armed uprising by the loyal lieges of oursaid lord the king; and for that reason all the lords temporal present in parliament, by the assent of the king, declared and adjudged the said Thomas, John, John, Thomas, and Ralph to be traitors for their armed uprising against their aforesaid liege lord, and that they should forfeit as traitors all the lands and tenements that they held in fee simple on 5 January, the eve of the feast of the Epiphany of our lord Jesus Christ, in the first year of the reign of our aforesaid lord [1400], or after, as the law of the land requires, together with all their goods and chattels, notwithstanding the fact that they were killed during the said armed uprising without due process of law.

On 13 Jan 1400 Thomas Despencer 1st Earl Gloucester (age 26) was beheaded at Bristol, Gloucestershire [Map].

Chronicle of the Betrayal of Richard II. [13 Jan 1400]. When the court of justice was over at Oxford, and Sir Thomas Blount was put to death, King Henry sent the Earl of Rutland and Sir Thomas Erpingham to seize the Lord Despencer (age 26) who was [formerly] Earl of Gloucester,¹ who took him and beheaded him; and the Earl of Rutland sent his head also to London.

Note 1. Thomas Despencer, son of Edward Lord Despencer, although he excused himself for the part he had taken on the plea of compulsion (Rot. Pari. iii. 451), was yet degraded from his title of Earl of Gloucester by Henry in his first Parliament. He escaped over the roofs of some houses at Cirencester, and fled to his castle of Cardilf. Hearing that King Henry had despatched a party to bring him to London, willing or unwilling, he disposed his affairs in the best manner he could, and, taking with him his jewels, entered a boat in the Severn ; but, when they had reached the middle of the river, the captain refused to carry him anywhere but to Bristol. An altercation then commenced ; twenty armed men, concealed in the hold, rushed upon deck ; he defended himself manfully, and wounded some of the sailors, but was overpowered, and carried to the mayor of Bristol. Henry wished to hâve had an interview with him before he was put to death ; but the second day after his capture the people cried out, 'Bring forth the traitors!' and, the mayor having failed to appease them, he was beheaded before the market-cross. His body was buried in the choir at Tewkesbury. (Monk of Evesham,Cotton. MS.TiberiusC. ix.) Henry gave to William Flaxman the cloak of motley velvet and furred damask which Lord Despencer wore when he was captured. (Rot. Pat. 1 Hen. IV. p. 5. m. 8.)