At last, in 1013, there came a Danish invasion of exceptional severity. The marauders dashed through the country from end to end; they took Canterbury and slew the good Archbishop Elfheah (St. Alphege), because he refused to pay them an exorbitant ransom. Then Eadric gathered together the Witan, without the king's presence, and, with infamous treachery to his benefactor, proposed to them to submit entirely to the Danes. So when Swegen came over again in the next year, the whole realm bowed before him, and the great men, headed by the traitor Eadric, offered him the crown. Only London held out for King Aethelred, and stood a long siege, till its citizens learnt that their master had deserted them and fled over sea to the Duke of Normandy, whose sister Emma he had married. Then they too yielded, and the Witan of all England took Swegen as their king. But the Dane died immediately after his election, and then the majority of the English refused to choose his son Cnut as his successor. They sent to Normandy for their old king, and did homage once more to Aethelred; but the traitor Eadric resolved to adhere to Cnut, because he had lately murdered the thegns of the Five Boroughs, and dreaded the wrath of their followers. So Eadric's Mercian subjects and some of the men of Wessex joined the Danes, and there was civil war once more in England, till Aethelred the Ill-counselled died in 1016. [Sidenote: =Edmund Ironside and Cnut, 1016.=] Then his followers chose in his stead his brave son Edmund II., who was called Ironside because of his prowess in war. The new king was a worthy descendant of Alfred, and would have made no small mark in better times, but he spent his short reign in one unceasing series of combats with Cnut, a man as able and as warlike as himself. The two young kings fought five pitched battles with each other, and fortune swayed to Edmund's side; but in the sixth, at Assandun (Ashington, in Essex), he was defeated, owing to the treachery of the wretched Eadric the Grasper, who first joined him with a large body of Mercian troops, and then turned against him in the heat of the battle (1016). Then Edmund and Cnut, having learnt to respect each other's courage, met in the Isle of Alney, outside the walls of Gloucester, and agreed to divide the realm between them. Cnut took, as was natural, the Anglo-Danish districts of Northumbria and the Five Boroughs, together with Eadric's Mercian ealdormanry. Edmund kept Wessex, Kent, London, and East Anglia. But this partition was not destined to endure. Ere the year was out the foul traitor Eadric procured the murder of King Edmund, and then the Witan of Wessex chose Cnut as king over the south as well as the north. The late king's young brothers and his two little sons fled to the Continent. [Sidenote: =The empire of Cnut.=]