and aid was given to Heriold against them." A next attempt in 819, again with help from the Obotrites, met with more success and some kind of settlement seems to have been reached with the sons of Gudfred, since Harald was joint king with two of them in 821. One of them probably was Horik the Elder. The Royal Annals report "On the emperor's [Louis] order Heriold was taken to his ships by the Obodrites and sailed back to his homeland to take over the kingdom. Two of the sons of Godofrid are said to have made an alliance with him to share the throne; two others were driven out of the country. But this is believed to have been done by trickery." An 821 entry mentions "Everything was quiet on the Danish front in this year, and Heriold was received as partner in the rule by the sons of Godofrid. This is believed to have caused the peaceful relations among them at this time." In 822, the general assembly was held in Frankfurt. The relevant entry mentions "Embassies from Nordmannia were also at this assembly , from Heriold as well as from the sons of Godofrid". In 823, tensions had appeared in Harald's relations with his co-rulers. Louis was asked to mediate. The Royal Annals report "Also Heriold came from Nordmannia, asking for help against the sons of Godofrid, who threatened to drive him out of his country. To explore this matter more thoroughly Counts Theothari and Hruodmund were sent to the sons of Godofrid. Traveling ahead of Heriold they carefully studied the dispute with the sons of Godofrid as well as the condition of the whole kingdom of the Norsemen and informed the emperor of all they could find out in these lands. They returned with archbishop Ebo of Rheims, who had gone to preach in the land of the Danes on the counsel of the emperor and with the approval of the Roman pontiff and had baptized many converts to the faith during the previous summer." Coupland notes that the entry reveals two things. First that "the political situation in Denmark remained extremely tense" and second that Louis continued to interfere in Danish affairs. The motivation behind his interest in the country is not stated in primary sources. The book "An Introduction to the Viking History of Western Europe, Viking Antiquities in Great Britain and Ireland" (1940)