Richard (2nd son, eventual heir), Earl of Cambridge, b. 1375, beheaded 5 Aug 1415; m. (1) before Jun 1408 (Papal dispensation to remain in marriage), Anne Mortimer, Countess of March; m. (2) Maud, daughter of Thomas, Lord Clifford. [Magna Charta Sureites]
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EARLDOM OF CAMBRIDGE (IV, 1)
RICHARD, styled "OF CONISBURGH," or "OF YORK" 2nd son of Edmund, DUKE OF YORK and EARL OF CAMBRIDGE, by his 1st wife, Isabel, daughter and coheir of Pedro, King of Castile and Leon, and brother to Edward, Duke of York and of Cambridge, was born at Coningsburgh Castle, co. York, about 1375. King Richard lI was his godfather. Knighted 26 July 1406; Ambassador to Denmark, August to December 1406. He was, on 1 May 1414, created in Parliament EARL OF CAMBRIDGE. Almoner of England, and Constable of Brimpsfield Castle. He married 1stly (Papal dispensation to remain in marriage contracted without consent of their parents, 10 Kal. June 1408), Anne (d), elder sister and coheir being eventually in her issue heir of Edmund, EARL OF MARCH (who died s.p. 19 January 1424/5), daughter and in her issue coheir of Roger (DE MORTIMER), EARL OF MARCH, by Eleanor, daughter of Thomas (DE HOLAND), EARL OF KENT. He married, 2ndly, about 1414, Maud, the divorced wife of John (NEVILL), 6th LORD LATIMER, daughter of Thomas (DE CLIFFORD), LORD CLIFFORD, by Elizabeth, daughter of Thomas (DE Ros), LORD Ros. Having conspired (with Scrope of Masham and Grey of Heton) to depose the King [Henry V] and set up in his room the Earl of March [the heir general of Edward III], he was executed 5 August 1415, at Southampton, being buried in the chapel of "God's house" there. All his honours were consequently forfeited. His widow died s.p., 26 August 1446, and was buried at the Abbey of Roche, co. York. [Complete Peerage II:494-5, XIV:136, (transcribed by Dave Utzinger)]
(d) This lady transmitted to her grandson Edward IV (who, through her was heir general of Edward III), the right to the Crown, her grandmother, Philippe, Countess of March, being only daughter and heir of Lionel, Duke of Clarence, 2nd surviving son of Edward III.
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Earl of Cambridge; Ambassador to Denmark 1406; Almoner of England; Constable of Brimpsfield Castle; having joined in a failed conspiracy to depose King Henry V, he sought the latter's mercy in most abject terms, which gained him only a beheading without the usual additional punishment for treason, all his honors being attainted.
He was beheaded, in accordance with the orders of Henry V, for treason with the French, before the Battle of Harfleur, which was before the Battle of Agincourt. Rather smashing scene in Ken Branagh's film of "Henry V" does the burly run-up to this, with a round turn.