By 1069, William still didn’t control his entire kingdom. His control didn’t go any further than York, about two hundred miles north of London, and there was still massive unrest in Northumbria. In January, William appointed one of his followers, Robert de Comines, as earl of Northumbria instead of trusting a local. He rode into Durham with a party of seven hundred men, despite warnings of rebels in the area, where they were surrounded and slaughtered. The rebels moved into York, where they killed many of William’s men. William returned to York and brutally put down the rebellion.
Over the next year, maybe emboldened by the rebellion in York or perhaps by coincidence, rebellions rose up in areas of northern and southwestern England. Meanwhile, Edgar Æthling began the largest rebellion against William in Northumbria. He sought the help of the king of Denmark, Sweyn II, who sent an invasion force of 250-300 ships led by his sons. They raided the east coast of England on their way, and they joined the Northumbrians against William when they arrived. The joint forces of Danes and Northumbrians attacked York again, retaking the city. At the same time, there was unrest on the Welsh border, and in Devon and Cornwall in southwestern England.
By this time, William the Conqueror had had enough of the rebellions and decided to put them all down once and for all. He sent deputies to deal with the southwest rebellions while he put down the Welsh rebellion. He then marched north to meet the Northumbrians and the Danes. The Northumbrians had retreated to the hills, Edgar Æthling had fled to Scotland, and the Danes had evacuated to their ships. William bribed the Danes with silver and gold if they would abandon the rebellion and leave. After they left, he turned to deal with the Northumbrians.
What followed during the winter of 1069-1070 was a particularly brutal and violent campaign by Norman forces that became known as the Harrying of the North. On Christmas 1069, William separated his forces into raiding parties to move from York north to Durham and southwest to Chester to find the Northumbrian rebels. The campaign covered over one hundred miles of northern England, destroying everything in its path. The soldiers burned whole villages and killed all the villagers, leaving the bodies to rot. They destroyed the land, crops and livestock so that another rebellion couldn’t take place and the survivors would starve to death over the winter.