East Francia
The ruler of East Francia was King Louis II (Louis the German), who had ruled since 843 and would continue to do so until 876.
Hedeby area
The ruler of Hedeby area was King Horik I, who was probably the King of all the Danish areas. He definitely held sway over Hedeby as he built a church there sometime before 852. He was supportive of the East Frankish missionary Ansgar's mission into the land of the Swedes, although Horik himself refused to convert to Christianity.