Arthur Plantagenet, 1st Viscount Lisle, KG (died 3 March 1542) was an illegitimate son of the English king Edward IV, half-brother-in-law of Henry VII, and an uncle of Henry VIII, at whose court he was a prominent figure and by whom he was appointed Lord Deputy of Calais (1533–40).

[1] The survival of a large collection of his correspondence in the Lisle Letters makes his life one of the best documented of his era.

In 1519 he and his wife, Elizabeth Grey Baroness Lisle, took possession of the lands that had belonged to her father (her brother and niece having both died).

Among the letters is one from Thomas Cromwell rebuking him for referring trivial matters back to the king and Council, criticising him for his inability to refuse a favour to anyone who asks for one, and hinting that Lady Lisle's dominant influence over him has made him something of a laughing stock.

In 1540, several members of the Plantagenet household in Calais were arrested on suspicion of treason, on the charge of plotting to betray the town to the French.

They survive in the Public Record Office, and were published in abridged form as the Lisle Letters, becoming a valuable historical resource for a critical period in English history.

[11] The arms of Edward, 4th Duke of York, emphasise his descent from Lionel of Antwerp, 1st Duke of Clarence (1338–1368), third son of King Edward III[citation needed] (on which basis the House of York claimed the throne), who married Elizabeth de Burgh, 4th Countess of Ulster (1332–1363).

He bore as crest: On a cap of maintenance gules turned up ermine, and inscribed in front with the letter A, a genet guardant per pale sable and argent, standing between two broom-stalks proper.