Despite the submission of the English nobles, resistance continued for several years. There were rebellions in Exeter in late 1067, an invasion by Harold's sons in mid-1068, and an uprising in Northumbria in 1068. In 1069 William faced more troubles from Northumbrian rebels, an invading Danish fleet, and rebellions in the south and west of England. He ruthlessly put down the various risings, culminating in the Harrying of the North in late 1069 and early 1070 that devastated parts of northern England. A further rebellion in 1070 by Hereward the Wake was also defeated by the king, at Ely.