Lionel of Antwerp, Duke of Clarence,, was an English prince, Earl of Ulster jure uxoris from 1347, Duke of Clarence from 1362, Guardian of England in 1345-1346, Lord Lieutenant of Ireland in 1361-1366, Knight of the Garter from 1361, second surviving son of King Edward III of England and Philippa of Hainault. He was named after his birthplace, at Antwerp in the Duchy of Brabant.

The House of York was a cadet branch of the English royal House of Plantagenet. Three of its members became kings of England in the late 15th century. The House of York descended in the male line from Edmund of Langley, 1st Duke of York, the fourth surviving son of Edward III. In time, it also represented Edward III's senior line, when an heir of York married the heiress-descendant of Lionel, Duke of Clarence, Edward III's second surviving son. It is based on these descents that they claimed the English crown. Compared with its rival, the House of Lancaster, it had a superior claim to the throne of England according to cognatic primogeniture, but an inferior claim according to agnatic primogeniture. The reign of this dynasty ended with the death of Richard III of England at the Battle of Bosworth Field in 1485. It became extinct in the male line with the death of Edward Plantagenet, 17th Earl of Warwick, in 1499.