Much information as to the life and character of Count D'Orsay is to be found in Richard Madden's _Literary Life and Correspondence of the Countess of Blessington_ (1855).
DORSET, EARLS, MARQUESSES AND DUKES OF, English titles one or more of which have been borne by the families of Beaufort, Grey and Sackville. About 1070 Osmund, or Osmer, an alleged son of Henry, count of Séez, by a sister of William the Conqueror, is said to have been created earl of Dorset, but the authority is a very late one and Osmund describes himself simply as bishop (of Salisbury). William de Mohun of Dunster, a partisan of the empress Matilda, appears as earl of Dorset or Somerset, these two shires being in early times united under a single sheriff. In 1397 John Beaufort, earl of Somerset (d. 1410), the eldest son of John of Gaunt, duke of Lancaster, and Catherine Swinford, was created marquess of Dorset; two years later, however, he was reduced to his former rank of earl of Somerset. In 1411 his brother Thomas, afterwards duke of Exeter, was created earl of Dorset, and in 1441 his youngest son Edmund obtained the same dignity. Two years later Edmund was created marquess of Dorset and still later duke of Somerset. Edmund's son Henry, duke of Somerset and marquess of Dorset, was attainted during the Wars of the Roses, and was beheaded after the battle of Hexham in May 1464, when the titles became extinct. In 1475 Thomas Grey, 8th Lord Ferrers of Groby (1451-1501), a son of Sir John Grey (d. 1461) and a stepson of King Edward IV., having resigned the earldom of Huntingdon, which he had received in 1471, was created marquess of Dorset (see below). He was succeeded in this title by his son Thomas (1477-1530), and then by his grandson Henry (c. 1510-1554), who was created duke of Suffolk in 1551. When in February 1554 Suffolk was beheaded for sharing in the rising of Sir Thomas Wyat, the marquessate of Dorset again became extinct; but in 1604 Thomas Sackville (see the account of the family under SACKVILLE, 1ST BARON) was created earl of Dorset (see below), and his descendant the 7th earl was created duke in 1720. In 1843 the titles became extinct.
THOMAS GREY, 1ST MARQUESS OF DORSET (1451-1501), was the elder son of Sir John Grey, 7th Lord Ferrers of Groby (1432-1461), by his wife Elizabeth Woodville, afterwards queen of Edward IV. He fought for Edward at Tewkesbury, and became Lord Harington and Bonville by right of his wife Cecilia, daughter of William Bonville, 6th Lord Harington (d. 1460); in 1475 he was created marquess of Dorset, and he was also a knight of the Garter and a privy councillor. After the death of Edward IV. Dorset and his brother Richard Grey were among the supporters of their half-brother, the young king Edward V.; thus they incurred the enmity of Richard duke of Gloucester, afterwards Richard III., and Richard Grey having been arrested, was beheaded at Pontefract in June 1483, while his elder brother, the marquess, saved his life by flight. Dorset was one of the leaders of the duke of Buckingham's insurrection, and when this failed he joined Henry earl of Richmond in Brittany, but he was left behind in Paris when the future king crossed over to England in 1485. After Henry's victory at Bosworth the marquess returned to England and his attainder was reversed, but he was suspected and imprisoned when Lambert Simnel revolted; he had, however, been released and pardoned, had marched into France and had helped to quell the Cornish rising, when he died on the 20th of September 1501.