Ethelbald swayed the sceptre of Mercia for forty-one years (716–57). He was evidently a strong and strenuous, if somewhat unscrupulous ruler. In the early part of his reign he had so completely cowed Wessex and conquered the other four southern kingdoms, that Bede, writing the concluding paragraphs of his history in 731, could say: “All the southern provinces up to the boundary of the Humber, with their respective kings, are subject to Ethelbald, King of the Mercians”. In 733 we find him capturing Somerton, the chief town of the Sumorsaetas; in 740 he turns his arms northwards and takes advantage of Eadbert’s absence on his Pictish campaign to ravage Northumbria. But in his last years fortune frowned upon him. In 750 Cuthred II., King of Wessex, apparently an active and valiant man, rose in rebellion, and in 752 won a great victory over Ethelbald at Burford on the slopes of the Cotswolds, putting him to ignominious flight. Never apparently did Mercia recover the supremacy over Wessex which she lost on that battlefield, and in 757 Ethelbald, who must have been an unpopular master of his household, perished by a night attack of his own guards. Notwithstanding his early friendship for St. Guthlac, Ethelbald was not a pious nor even a moral king. There is preserved a remarkable letter addressed to him by St. Boniface,[112] in which the apostle of Germany, while praising the vigour and justice of his government, rebukes him for his outrageous profligacy, and expresses his fear that some great national judgment, like the Moorish conquest of Spain, will fall upon the kings and peoples of England for their luxury and immorality--a remarkable prophecy, as it must have seemed to later generations, of the Danish ravages.