that Ansgar went ashore in Birka, which was in King Björn's kingdom. According to the Vita, King Björn discussed the arrival of the missionaries with his men, then announced that they were free to preach. Apart from the numerous Christian prisoners at the place, several people seemed interested in the new faith. To these belonged Hergeir, the chief of the port, who was a prominent adviser to King Björn. After having been baptized, he built a church on his personal land. Ansgar stayed in Sweden for one and a half year and then returned to the Emperor's court in 831. Björn gave him a letter to bring to Louis, "written in the particular way of the Swedes", thus presumably with runic script. In his stead an auxiliary bishop, Gautbert, was appointed for Sweden. However, his activity was cut short several years later. An anti-Christian riot broke out, not supported by the king. Gautbert's nephew Nithard was killed, and Gautbert and his retainers driven out of the country. It is not explicitly said if Björn was still alive at the time. The account indicates that the Swedish king had limited control over people. The extent of Björn's kingdom The Vita is vague about the geography of Sweden, and there is no way of telling if the power of King Björn extended beyond the Mälaren Valley. The Vita Karoli Magni, written around the time of Ansgar's visit, has a short description of the Baltic region: "There is a bay which stretches from the western ocean in eastern direction, of unknown length but with a breadth that may not exceed 150 kilometers, while it is less at many sites. Many people live around this bay, Danes and Swedes, which we call Norsemen, live both on the northern shore and all the islands in the bay. The southern coast is however inhabited by Slavs, Aesti and a number of other people". This account, together with other sources from the 9th century, seems to indicate that the Danes and Swedes were the main Nordic peoples known to the continental authors, and that Björn's sphere of power was not merely local. References 9th-century Swedish people 9th-century rulers in Europe Swedish monarchs