While Erling Skakke was absent on an expedition to Denmark, a band of rebels was organized under the leadership of a new pretender, Olaf, a son of King Eystein Magnusson's daughter Maria, in her marriage with the chief Gudbrand Skafhoggson, who fell with King Inge in the battle at Oslo. Olaf was brought up by an influential man named Sigurd Agn-Hat. Probably from the latter's surname the adherents of Olaf were called Hat-Swains (Hættesveiner). The Hat-Swains proclaimed Olaf king, and went through the Uplands, and sometimes down to Viken, or east to the forest settlements. At Rydjokel, near Lake Oiern, they surprised Erling Skakke and his men early one morning, and in the fight that followed killed several of Erling's men and drove the remainder down to their ships. Because Olaf did not succeed in capturing Erling, although the odds were all in his favor, he was afterward called Olaf the Unlucky (Ugæva). The following spring the Hat-Swains met Erling in battle at Stanger, in the eastern part of Viken, where Erling won a decisive victory. Sigurd Agn-Hat and many others of Olaf's men fell here. Olaf escaped by flight, went south to Denmark, and spent the winter in Aalborg, where he died of sickness the following spring (1169). The interruption of the navigation between Norway and Denmark under the decree of King Valdemar worked great hardship to the Norwegians, especially the inhabitants of Viken, and Erling Skakke was finally induced to open negotiations for peace. He spent a winter in Denmark, and in the following spring peace was finally concluded, the terms being that Viken should be under the sovereignty of the Danish king, but Erling was to hold it in fief as King Valdemar's vassal with the title of Earl. Erling returned to Norway, and the peace with Denmark was afterward well preserved.