Cambridge's brother-in-law and cousin, on the throne). As noted above, Richard had married Anne de Mortimer, this giving their son (and the House of York), through Lionel of Antwerp, a more senior claim than that of both the House of Lancaster, which descended from a younger son than Lionel, and the House of Tudor, whose legitimized Beaufort ancestors had been debarred from the throne. In 1460 Richard, 3rd Duke of York, claimed the throne on this basis, but an Act of Accord meant he instead became heir. However he was killed later that year, causing his son Edward to take over. William of Windsor (1348–1348) William of Windsor (24 June 13485 September 1348), 7th son. Died from the plague as an infant. Thomas of Woodstock, Duke of Gloucester (1355–1397) Thomas of Woodstock, 1st Duke of Gloucester (7 January 13558/9 September 1397), eighth son. He was one of the Lords Appellant influential under Richard II, was murdered or executed for treason, likely by the order of Richard II; his eventual heir was his daughter Anne, who married into the Stafford family, whose heirs became the Dukes of Buckingham. Henry Stafford, 2nd Duke of Buckingham, descended on his father's side from Thomas of Woodstock, and on his mother's side from John Beaufort. Arms of the sons of Edward III Daughters Isabella, Countess of Bedford (16 June 1332), married Enguerrand VII de Coucy, 1st Earl of Bedford. Had issue. Joan of England (February 13342 September 1348) died of the plague in Bordeaux, on her way to marry Peter of Castile. No issue. Blanche (1342), died young. Mary of Waltham (10 October 1344September 1362), married John IV, Duke of Brittany. No issue. Margaret, Countess of Pembroke (20 July 1346October/December 1361), married John Hastings, 2nd Earl of Pembroke. No issue. References Wars of the Roses