the female side from Blanche of Lancaster, wife of John Gaunt, daughter of Henry of Grosmont, 1st Duke of Lancaster (–1361), descended from Edmund Crouchback, 1st Earl of Lancaster, the second son of King Henry III (1216–1272), the great-grandfather of King Edward III. A legend was developed, although without foundation, claiming that Edmund Crouchback was older than his brother King Edward I and had been passed over in the succession because of physical infirmity. Legitimized male heirs (Beaufort) John of Gaunt's legitimized heirs were the Beaufort family, his descendants by his mistress, and later his wife, Katherine Swynford. Gaunt's great-granddaughter from this union, Margaret Beaufort (1443–1509), was the last legitimate descendant of the Beauforts and married into the House of Tudor, producing a single child Henry Tudor, Earl of Richmond, who in 1485 at the Battle of Bosworth seized the throne from his mother's second cousin King Richard III (1483–1485) and ruled as King Henry VII (1485–1509). While the Beaufort offspring had been legitimized by Richard II by act of parliament and papal bull, after Gaunt's eventual marriage to Katherine Swynford, this was later, by letters patent issued by Henry IV, conditioned that they be barred from ascending the throne. Undeterred by this, and following the 1461 seizure of the throne by the Yorkist King Edward IV (1461–1483) from the Lancastrian King Henry VI (1422–1461), the Tudors claimed precedence to the Yorks the last of whom, King Richard III was killed at the Battle of Bosworth in 1485. The present Somerset family, Dukes of Beaufort, of Badminton House in Gloucestershire, are illegitimate direct male descendants of John of Gaunt, being illegitimate descendants of Henry Beaufort, 3rd Duke of Somerset, first cousin of Margaret Beaufort (1443–1509). They assumed "Somerset" as their family surname, but bear as arms the ancient arms of the Beaufort family: The royal arms of King Edward III within a bordure compony argent and azure, and in 1682 were created Dukes of Beaufort. Edmund of Langley, 1st Duke of York (1341–1402) Edmund of Langley, 1st Duke of York (5 June 13411 August 1402), fifth son. His descendants were the Yorks. He had two sons: Edward of Norwich, 2nd Duke of York, killed fighting alongside Henry V at the Battle of Agincourt, and Richard of Conisburgh, 3rd Earl of Cambridge, executed by Henry V for treason (involving a plot to place heir presumptive Edmund Mortimer, 5th Earl of March,