To give dignity to the occasion, he took steps to have his son crowned with much magnificence, and shortly after sent his daughter Rikissa with great pomp and a rich dower to the frontier of Norway, where she was met by the king of that country and was married with stately ceremony to his son. The next year Birger's mother died, and as there was a prophecy that her family would remain in power as long as her head was up, he had her buried upright, being walled up in a pillar in Bjelbo Church so that her head should never droop. Birger Jarl belonged to a great family called the Folkungers, who long held all the power in Sweden, and many of whom had been aspirants for the throne. These were so angry at being deprived of what they had hoped for that they determined to take the throne by force, and their leaders went to Denmark and Germany, where they collected a large army. When they landed in Sweden many of the people of that country joined them, and though Birger had also a large force he began to fear the result. He therefore sent his chancellor, Bishop Kol, to ask for a personal interview with the leaders of the opposite force, with solemn promises of safety. Yielding to the bishop's persuasions, the chiefs accompanied him across the river that separated the two armies. Then Birger did a dastardly act. No sooner had the chiefs come within his power than he had them seized and beheaded on the spot as rebels. Thus fell a number of the leading men of Sweden, and, the leaders fallen, Birger attacked and easily dispersed their army, sparing the Swedes, but cutting to pieces all the Germans that could be overtaken. Thus he added greatly to the power of his family, but by an act of treachery and perjury for which Archbishop Lars laid upon him a heavy penance. As for Bishop Kol, who had been made the innocent agent in this shameful deed, he never read mass again, and finally resigned his office and left his country, journeying as a pilgrim to the Holy Land in expiation for his involuntary crime. He never found peace and rest until he found them in the grave. Birger Jarl by these means rose to be the mightiest man in the north. His son was king of Norway, his daughter was queen of Sweden, and his daughter-in-law was a princess of Denmark, for when Valdemar became twenty years of age he sought and won for his bride the beautiful Danish Princess Sophia. The marriage was one of great pomp, a great hall being built for the occasion, where the courtiers appeared in new-fashioned dresses of rich stuffs, and there were plenty of banquets, games, dances, and even tilts and tournaments, all conducted according to the noblest custom of the times.