Although Fortune appeared to lavish her smiles upon the Conqueror, bitter discontent was brooding in the hearts of the English, who saw themselves stripped one by one of their liberties and privileges, and whenever they met with the Normans in small parties the people set on them and slew them without mercy. An insurrection at last broke out in the north of England, headed by the Earls Morcar and Edwin, who bitterly regretted their short-sighted policy in not having supported Edgar Atheling on the throne. Before appealing to arms, these powerful nobles had secured the assistance of the Welsh; of Malcolm, King of Scotland; and of Sweyn, King of Denmark. Edwin was opposing the King because the latter, who had promised his daughter to the earl in marriage, would not keep his word. William knew the importance of celerity in quelling a revolt, especially when supported by such powerful leaders. He advanced, therefore, with rapid marches towards the north. On his way he gave orders to fortify Warwick Castle, which he committed to the government of Henry de Beaumont, one of his nobles; while Nottingham Castle was entrusted to William Peverell, another Norman leader. Using the utmost expedition, the Conqueror reached York before the promised succour had arrived or the English were prepared for resistance; the city threw open its gates to the Conqueror. "Their submission was received," as Lingard says, "with a promise of forgiveness, and a resolution of vengeance." The king at this time fortified several castles in different parts of the country, and thus securing possession of the military power, left Edwin and Morcar, whom he pretended to spare, destitute of all support, and the two earls had no other resource than to appeal to William's clemency. A peace which he made with Malcolm, who did him homage for Cumberland, seemed at the same time to deprive them of all prospect of foreign assistance. Edgar Atheling, dreading the unscrupulous policy of William, yielded to the advice of Cospatrick, a powerful Northumbrian noble, and fled with him, accompanied by his mother Agatha and his two sisters Margaret and Christina, to Scotland, where they were hospitably received by Malcolm, who soon afterwards espoused the former princess--the latter became a nun.