Suffolk, other creations. The [1st] Duke, for all his disgrace, had never been attainted and his son John de la Pole succeeded him in the titles. John married Elizabeth of York, sister of Edward IV and Richard III, with the result that his son the 3rd Duke (and 6th Earl) of Suffolk became after the Tudors had ascended the throne a potential claimant to it and a very real embarrassment to the new dynasty. The de la Poles, at any rate such of them who had not gone abroad or were content to live in obscurity, were accordingly liquidated by the usual Tudor methods of trumped up attainders and beheadings. [Burke's Peerage]
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BARONY OF POLE (III)
EARLDOM OF SUFFOLK (IX, 5)
MARQUESSATE OF SUFFOLK (II)
DUKEDOM OF SUFFOLK (II)
EARLDOM OF PEMBROKE (XVI, 2)
JOHN (DE LA POLE), DUKE OF SUFFOLK [1448], MARQUESS OF SUFFOLK [1444], and EARL OF SUFFOLK [1385], also, apparently, EARL OF PEMBROKE [1447] (but as that Earldom was never recognized to him or to his descendants no further notice of it is here taken), son and heir, was born 27 September 1442; joint Constable (in survivorship with his mother and father) of Wallingford Casde and Steward of the Chiltern Hundreds, 27 November 1445, (with his wife) 6 August 1461-August 1483, and sole, 21 September 1485-March 1488/9. Having married Elizabeth, 2nd daughter of Richard, DUKE OF YORK, he fought as a Yorkist at the battles of St. Albans, 17 February, Ferrybridge, 28 March, and (presumably) Towton, 29 March 1461; was Lord High Steward for the Coronation of (his wife's brother) Edward IV, 28 June 1461, from whom he received confirmation as Duke of Suffolk, 23 March 1462/3; and he bore St. Edward's sceptre at the Coronation of Elizabeth (Wydevill), the Queen Consort, 26 May 1465. In the Parliament of 1464-65 the attainder of 1387/8 was reversed, whereby the Barony of de la Pole (created according to modern doctrine by the writ of 1366) was revived and he probably (then or later) became LORD DE LA POLE. He was a Commissioner of array for cos. Oxford, Berks, Norfolk and Suffolk ex parte Edward IV, 1469-72, and was among the peers and others who swore to accept Edward, Prince of Wales, as heir to the Crown, 3 July 1471. High Steward of Oxford University, circa 1472; K.G. circa 1473; took part in Edward IV's expedition to France in 1475; Lieutenant of Ireland, 10 March-July 1478; Bearer of the sceptre with the dove at the Coronation of (his wife's brother) Richard III, 6 July 1483, and of the Queen's sceptre at that of (his wife's niece) Elizabeth (of York), the Queen Consort, 25 November 1487. He married, 1stly, between 28 January and 7 February 1449/50, his father's ward, Margaret, only daughter and heir of John (BEAUFORT), DUKE OF SOMERSET, by Margaret, widow of Sir Oliver ST. JOHN, sister and heir of John BEAUCHAMP, and daughter of John BEAUCHAMP, of Bletsoe. This child marriage was dissolved before 6 March 1452/3. He married, 2ndly, before October 1460, Elizabeth, sister of EDWARD IV and RICHARD III, 2nd daughter of Richard (PLANTAGENET), 3rd DUKE OF YORK, by Cecily, daughter of Ralph (NEVILL), 1st EARL of WESTMORLAND. He died between 29 October 1491 and 27 October 1492, being buried at Wingfield. M.I. there and at Ewelme. His widow, who was born 22 April 1444 at Rouen, died between 7 January 1502/3 and 3 May 1504, and was bur. with him. M.I. [Complete Peerage XII/1:448-50, XIV:602, (transcribed by Dave Utzinger)]
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John de la Pole, 2nd Duke (1442-91), married Elizabeth, sister to Edward IV and Richard III and from this marriage sprang John, Earl of Lincoln (c1464-1487), Edmund, Earl of Suffolk (c1472-1513, executed by Henry VIII), two churchmen, four daughters, and Richard, on whose death at the battle of Pavia (1525) the line became extinct. (Chambers Biographical Dictionary)