King Henry V of England married Catherine of Valois, the French king's niece, on June 2, 1420, in an effort to consolidate power over both nations. Henry was a popular and successful leader, but his territorial and diplomatic gains deteriorated after his sudden death from illness in 1422, and his dream of English rule over France never came to be.
The widowed Catherine began a relationship with the Welsh noble Owen Tudor. They may have been secretly married, and she definitely bore him five children. Catherine and Owen Tudor's sons became earls in the reign of her son Henry VI, and their grandson was King Henry VII of England.