In 1067, during William’s absence in Normandy, rebellions broke out in the south and west of England; and when the King returned, he began the conquest of the western portions of the country. Exeter submitted after a siege lasting eighteen days, but no sooner had the western rebellion been subdued than Mercia and Northumbria were in revolt. Next year the King marched north and reached York, the inhabitants of which rather unexpectedly surrendered their city; and on William’s departure he left William de Malet, one of his Norman knights, in charge of it. But after a few months the men of York again rose in revolt and Malet was hard pressed, although he succeeded in holding out till relieved by the King. All over England these rebellions were going on. But none was more than partly successful; and for the reason that ‘Englishmen could not agree to act together. One district rose at one time and one at another. Some were for Sweyn, some for Edgar, some for the sons of Harold; Edwin and Morcar were for themselves. So there was no common action against William, and the land was lost bit by bit.’ In the autumn of 1069 it seemed as if there really was to be made in the North of England a united effort to throw off the yoke of the Frenchmen. Sweyn Ulfsson, King of Denmark, sent a large fleet of ships into the Humber under the command of Jarl Asbiorn, his brother. Outside the walls of York the Danish shipmen were joined by Edgar the Aetheling, by Gospatric, the dispossessed successor of Oswulf, and by Jarl Waltheof, Siward’s son. Then began a second siege of York. The French garrison, under William de Malet and Gilbert of Gaunt, retreated to the two wooden castles which William had caused to be erected, and set fire to the portions of the city surrounding these in order to give themselves greater security. For two days the flames raged, destroying many houses and the Minster of St. Peter. Meanwhile the allies entered the city. Then the Normans attempted a sally from their castles, but unsuccessfully. Their forces were cut to pieces, and William de Malet and Gilbert of Gaunt were taken prisoners. So far all had gone well with the armies of Jarl Asbiorn and Jarl Waltheof, and had they only held the city when taken and awaited the arrival of King William, they would have had every chance of repeating their success. But a fatal dissension once more broke out, and Asbiorn’s men went back to their ships and sailed first to North Lincolnshire and then to Holderness, while Waltheof withdrew his men to the marshes between the Trent and the Ouse.