Katherine Swynford: Katherine became the third wife of John of Gaunt, Duke of Lancaster, and their descendants were the Beaufort family, which played a major role in the Wars of the Roses. Henry VII, who became King of England in 1485, derived his claim to the throne from his mother Lady Margaret Beaufort, who was a great-granddaughter of Gaunt and Katherine Swynford. (24x's great grandparents)
John of Gaunt 1st Duke of Lancaster - As a younger brother of Edward, Prince of Wales (Edward, the Black Prince), John exercised great influence over the English throne during the minority of his nephew, Richard II, and during the ensuing periods of political strife, but was not thought to have been among the opponents of the king. John of Gaunt's legitimate male heirs, the Lancasters, included Kings Henry IV, Henry V, and Henry VI.
Tombs of Katherine Swynford and her daughter Joan Beaufort- c.1640 - The three preceding houses of English sovereigns from 1399, the Houses of Lancaster, York and Tudor, were descended from John of Gaunt through, Henry Bolingbroke, Joan Beaufort and John Beaufort.