Richard wanted to make peace with the English king. He gave his sister Emma of Normandy in marriage to King Ethelred. Ethelred gave Emma the city of Exeter as a dowry. This turned out to be an important marriage as it later gave Richard's grandson, William the Conqueror, a claim to the throne of England. In 1013 when Sweyn Forkbeard invaded England, Emma with her two sons Edward and Alfred fled to Normandy. After losing his throne King Ethelred followed shortly. Soon after the death of Ethelred, Cnut, King of England forced Emma to marry him. Duke Richard was forced to recognize the new regime as his sister was again Queen. 