By summer more rebellions had broken out. At the same time others were fleeing England. Edgar Atheling along with his mother and sisters left for Scotland where they were welcomed. In the North strong anti-Norman groups were gathering around York. Earl Edwin and his brother Morcar left William's court to join the rebels in the north. William then built a castle at Warwick. This caused the Earls and others to give in to William. Other castles followed. William then entered York where others came to him and submitted. He then negotiated with the king of Scots to prevent any invasions of England from the north. But his campaign in the North was not as effective as he thought. In 1069 a second uprising developed into a war. The men William left in charge had been killed. A small Norman force was holding out in York when William came to their aid. After building another castle William left Earl William FitzOsbern in charge. For the next five months the north was quiet. But the northern English leaders had sent word to King Swein in Denmark offering him the crown if he could defeat the Normans. Swein sent a Danish fleet to England. 