... were both descended from Edward III. They were third cousins, once removed; Henry was from a later generation than Richard, although he was born just five years later (1457 compared with 1452).
Richard was Edward's great–great–grandson, via the 1st and 3rd Dukes of York and Richard, Earl of Cambridge. The Earl of Cambridge, Richard III's grandfather, was the son of the 1st Duke of York, brother of the 2nd, and father of the 3rd.
Henry VII's mother, Lady Margaret Beaufort, was the great–granddaughter of John of Gaunt, the 1st Duke of Lancaster in the second creation. Henry was thus Edward III's great–great–great–grandson.
John of Gaunt was the third surviving son of Edward III. He had two daughters and a son with his first wife, Blanche of Lancaster (daughter of the first Duke of Lancaster). The son, Henry Bolingbroke, would become King Henry IV. Blanche died in 1368, and three years later Gaunt married Constance of Castile – daughter of Peter, the King of Castile. They had one child: Catherine of Lancaster, who married King Henry III of Castile.
During his second marriage, to Constance, Gaunt had four children with his mistress, Katherine Swynford. Following Constance's death in 1394 he married Katherine, and their four children were legitimised by King Richard II, who was Gaunt's nephew. How ironic then that Richard was later usurped, and effectively murdered, by Gaunt's eldest son, and his cousin – Henry Bolingbroke (Richard II was the son of Edward of Woodstock, the eldest son of Edward III and Gaunt's elder brother – known today as the Black Prince).
Lady Margaret Beaufort (the mother of Henry Tudor, who became King Henry VII of England) was the grand–daughter of John Beaufort, 1st Earl of Somerset – the eldest of the four children of John of Gaunt and Katherine Swynford.
In 1486 (one year into his reign), Henry VII married Elizabeth of York, the daughter of King Edward IV. This cemented his claim to the throne by uniting the house of Lancaster, into which he had been born, with that of York.
© Haydn Thompson 2021