Dictionary of National Biography, 1885-1900/Thurkill (fl.1009)
THURKILL or THORKILL the Earl (fl. 1009), Danish invader, is said to have come to England to avenge a brother, possibly one of the victims of the massacre of St. Brice's Day, 13 Nov. 1002 (Emmæ Anglorum Reginæ Encomium ap. Maseres, Selecta Monumenta, p. 7). Thurkill commanded the Danish fleet which appeared off the south-east coast in August 1009 (A.-S. Chron. ii. 115, Rolls Ser.). Off Thanet he was joined by a second Danish fleet, commanded by Heming and Eglaf (Flor. Wig. i. 160–1, Engl. Hist. Soc.), and together they came to Sandwich. For the next two or three years Thurkill probably led the great Danish raids in the southern and eastern counties, but towards the end of that time is thought to have shown a leaning towards Christianity. He was present at the murder of Ælfheah [q. v.], archbishop of Canterbury, in 1012, but, in spite of William of Malmesbury's statement (Gesta Regum, i. 207, Rolls Ser.), probably tried to save the archbishop, offering gold and silver—everything save his beloved ship—in ransom for him (Thietmar of Merseburg ap. Freeman, Norman Conquest, i. 668). Soon after this it may be inferred that Thurkill embraced Christianity, and with forty or forty-five Danish ships (Encomium, loc. cit.) entered the service of King Ethelred or Æthelred II [q. v.] Thurkill's change of side seems to have hastened the long-contemplated invasion of England by Sweyn or Swegen [q. v.] in 1013 (ib.) He was certainly one of England's most valiant and capable defenders against Sweyn. He was with Ethelred in London in 1013, and helped the citizens to beat off Sweyn's attack; and when that city and the country at large had submitted, it was to Thurkill's fleet lying at Greenwich that King Ethelred fled for refuge. At Greenwich Thurkill remained during the winter of 1013–14, like Sweyn himself, levying contributions at will upon the surrounding land (Flor. Wig. i. 168).
It is uncertain when Thurkill forsook the English side and joined Cnut, but his fleet went over with Edric or Eadric Streona [q. v.] in 1015, and Thurkill himself was undoubtedly Cnut's strongest supporter in the war with Edmund Ironside. He remained in England when Cnut returned to Denmark on his father's death, but is said to have followed shortly, thinking it safer so to prove his loyalty, and swore allegiance to Cnut (Encomium, vol. ii. pp. i and iv). He left thirty ships in England, however, and urged Cnut to return thither. In the campaign which followed Cnut's return to England he was prominent, leading the Danish forces at Sherstone in Wiltshire (Geoffrey Gaimar, Lestorie des Engles, ap. Petrie, Mon. Hist. Brit. i. 816), and being present with Cnut at the battle of Assandun in Essex (Encomium, ii. 8). Cnut acknowledged his great debt to Thurkill when in 1017 he divided England into four earldoms by giving him that of East-Anglia (A.-S. Chron. ii. 124). Three years later Thurkill was fittingly associated with Cnut in the building and consecration of the church at Assandun by Archbishop Wulfstan of York (ib. ii. 125). Thurkill, too, was a distinguished patron of St. Edmund's Abbey, and in this same year replaced the secular clerks there by monks (Memorials of St. Edmund's Abbey, i. 47, 126, 340). Cnut appears to have distrusted, or been jealous of, Thurkill, for in 1021 he banished him with his wife Eadgytha (Flor. Wig. i. 183), possibly the widow of Eadric Streona, and, if so, a daughter of King Ethelred (Norman Conquest, i. 670). Two years later, however, Cnut and Thurkill were reconciled, and, though the latter does not seem to have ever returned to England, he was made Cnut's viceroy in Denmark and guardian of his son, probably the one intended to succeed Cnut there (A.-S. Chron. ii. 126). Thurkill's own son Cnut brought as a hostage for his father to England. Osbern's statement (De Translatione Corporis S. Elphegi ap. Wharton, Anglia Sacra, ii. 144) that Thurkill was killed on his return to Denmark is untrustworthy, and the date and manner of his death are unknown.[See, in addition to the chief authorities mentioned in the text, Annales Monastici, vol. ii. (Rolls Ser.); Simeon of Durham's Hist. Eccl. Dunelm. ii. 140, 145, 154, 156; Henry of Huntingdon's Hist. Angl. p. 186; Brompton ap. Twysden's Decem Script. pp. 888, 906.]