Page "House of York" Paragraph 1

Edmund of Langley had two sons, Edward, and Richard of Conisburgh.

Edward succeeded to the dukedom in 1402, but was killed at the battle of Agincourt in 1415, with no issue.

His younger brother married Anne de Mortimer, a great-granddaughter of Lionel of Antwerp, the second son of Edward III.

Anne was also heiress to the earldom of March, following the death of her brother Edmund, 5th Earl in 1425.

Edmund Mortimer was the son of Roger Mortimer, 4th Earl of March, who had been named heir presumptive of Richard II, prior to the usurpation of the House of Lancaster, in the person of Henry Bolingbroke, in 1399.