Joan; married 1st as his 2nd wife Edmund of Langley (died 1 Aug 1402), 1st Duke of York of the 1385 creation and 5th son of Edward III; married 2nd after 1 Aug 1402 but before 9 Aug 1404, as his 2nd wife, 5th Lord (Baron) Willoughby de Eresby; married 3rd c 6 Sep 1410 3rd Lord (Baron) Scrope (of Masham) (dsp, beheaded 5 Aug 1415); married 4th between autumn 1415 and 27 April 1416, as his 1st wife, 1st and last Lord (Baron) Vessy and dsp 12 April, 1434. [Burke's Peerage, p. 2904]
-------------------------
William Willoughby married 2nd after 1 Aug 1402 but before 9 Aug 1404, as the 2nd of her four husbands, Joan, sister and coheir of 4th/6th and last Earl of Kent of the 1321 creation. [Burke's Peerage, p. 3032]
-------------------------
He [Edmund Plantagenet] married, 2ndly, Joan, sister and coheir of Edmund (DE HOLAND), 4th EARL OF KENT, daughter of Thomas, 2nd EARL OF KENT, by Alice, daughter of Richard (FITZALAN), 10th or 3rd EARL OF ARUNDEL. He died 1 August 1402 at Langley, aged 61, and was buried there with his 1st wife. Will dated 25 November 1400, proved at Lambeth, 6 October 1402. His widow married, before 9 August 1404, as his 2nd wife, William (DE WILLOUGHBY), 5th LORD WILLOUGHBY, who died 4 December 1409, She married, 3rdly (licence 6 September 1410, to marry in the chapel of Faxflete, co. York), as his 2nd wife, Henry (LE SCROPE), 3rd LORD SCROPE (of Masham), who died s.p. 5 August 1415, being beheaded at Southampton. She married, 4thly, between Michaelmas 1415 and 27 April 1416 (pardon for marrying without licence, 14 August following, as his 1st wife, Henry (BROMFLETE), LORD VESSY, who died s.p.m. 16 January 1468/9. She, who was said to be aged 36 in 1416, died s.p. 12 April 1434. [Complete Peerage XII/2:895-9, (transcribed by Dave Utzinger)]