Dictionary of National Biography, 1901 supplement/Beaufort, Edmund (1438?-1471)
BEAUFORT, EDMUND, styled fourth Duke of Somerset (1438?–1471), born about 1438, was second of the three sons of Edmund Beaufort, second duke of Somerset [q. v.], by his wife Eleanor, daughter of Richard de Beauchamp, earl of Warwick [q. v.] After the defeat of the Lancastrians in 1461, Edmund was brought up in France with his younger brother John, and on the execution of his elder brother Henry Beaufort, third duke of Somerset [q. v. Suppl.], Edmund is said to have succeeded as fourth duke. He was so styled by the Lancastrians in February 1471, but his brother's attainder was never reversed, and his titles remained forfeit. In a proclamation dated 27 April 1471 Edmund is spoken of as 'Edmund Beaufort, calling himself duke of Somerset.' He returned from France when Edward IV was driven from the throne by Warwick's defection, and on 4 May 1471 commanded the van of the Lancastrian army at the battle of Tewkesbury, His position was almost unassailable (see plan in Ramsay, ii. 379), but, for some unknown reason, after the battle began he moved down from the heights and attacked Edward IV's right flank. He was assailed by both the king and Richard, duke of Gloucester, and was soon put to flight, his conduct having practically decided the battle in favour of the Yorkists (Arrivall of Edward IV, Camden Soc. pp. 29-30; Warkworth, p. 18; Hall, p. 300). He was taken prisoner, and executed two days later, Monday, 6 May 1471; he was buried on the south side of Tewkesbury Abbey, under an arch (Dyde, Hist. and Antiq, of Tewkesbury, pp. 21-2). His younger brother John had been killed during the battle, and as both died unmarried, 'the house of Beaufort and all the honours to which they were entitled became extinct.'