The reign of King Æthelred the Unready witnessed the resumption of Viking raids on England, putting the country and its leadership under strains as severe as they were long sustained. Raids began on a relatively small scale in the 980s but became far more serious in the 990s, and brought the people to their knees in 1009–12, when a large part of the country was devastated by the army of Thorkell the Tall. It remained for Swein Forkbeard, king of Denmark, to conquer the kingdom of England in 1013–14, and (after Æthelred's restoration) for his son Cnut to achieve the same in 1015–16. The tale of these years incorporated in the "Anglo-Saxon Chronicle" must be read in its own right, and set beside other material which reflects in one way or another on the conduct of government and warfare during Æthelred's reign. It is this evidence which is the basis for Keynes's view that the king lacked the strength, judgement and resolve to give adequate leadership to his people in a time of grave national crisis; who soon found out that he could rely on little but the treachery of his military commanders; and who, throughout his reign, tasted nothing but the ignominy of defeat. The raids exposed tensions and weaknesses which went deep into the fabric of the late Anglo-Saxon state, and it is apparent that events proceeded against a background more complex than the chronicler probably knew. It seems, for example, that the death of Bishop Æthelwold in 984 had precipitated further reaction against certain ecclesiastical interests; that by 993 the king had come to regret the error of his ways, leading to a period when the internal affairs of the kingdom appear to have prospered.