Rory Naismith attribute it to an unsuccessful attempt by Eadwig to promote a powerful new faction at the expense of the old guard. According to Dunstan's first biographer, who only named himself as "B": "King Eadwig was totally abandoned by the people north [of the Thames]. They despised him for his imprudent discharge of the power entrusted to him. The wise and sensible he destroyed in a spirit of idle hatred, replacing them with ignoramuses like himself to whom he took a liking." However, this is the view of a partisan of Dunstan, who was Eadwig's enemy. B was probably in exile with Dunstan when the division took place. Oda forced Eadwig to divorce his wife Ælfgifu on the ground that they were too closely related, but Edgar was on good terms with her when he became king. Four versions of the Anglo-Saxon Chronicle mention the division of the kingdom, and they all state that Edgar "succeeded" to the kingship of the Mercians, as if it was a normal and expected event. Manuscripts D and F of the Anglo-Saxon Chronicle (ASC D and ASC F), date the division to 955, whereas ASC B and ASC C correctly date it to 957. The difference in dates may be because it was agreed in Eadred's reign that the kingdom would be divided between the brothers, but he died before Edgar was old enough to act in person and had to wait until he reached the age of majority of fourteen in 957. Charter attestations show that the magnates did not decide which court to attend on the basis of personal loyalty: ealdormen and bishops with jurisdictions south of the Thames stayed with Eadwig, while those north of it served Edgar. Keynes comments: "One need not imagine that the unity of England would have been regarded in the 950s as something necessarily desirable for its own sake, not least because it was of such recent creation." Almost all thegns who had attested Eadwig's charters before the division stayed with him. The historian Frederick Biggs argues that the division was a revival of the earlier Anglo-Saxon practice of joint kingship, against the opposition of the church, and Bishop Æthelwold complained that Eadwig had "through the ignorance of childhood dispersed his kingdom and divided its unity". Eadwig retained some degree of seniority, as he attested charters as "King of the English", whereas Edgar was usually