which  North Germanic tribe did Horik I reigned as sole King of
Horik I Horik I (died 854) reigned as sole King of the Danes from 827 to his violent death in 854. His reign was marked by Danish raids on the Franco-German empire of Louis the Pious, son and successor of Charlemagne.
Chlothar II Chlothar II (or "Chlotar", "Clothar", "Clotaire", "Chlotochar", or "Hlothar"; 584–629), called the Great or the Young, was King of Neustria and King of the Franks, and the son of Chilperic I and his third wife, Fredegund. He started his reign as an infant under the regency of his mother, who was in an uneasy alliance with Clothar's uncle Guntram, King of Burgundy (d. 592). Clothar assumed full power over Neustria upon her death in 597; though rich this was one of the smallest portions of Francia. He continued his mother's feud with Queen Brunhilda of Austrasia with equal viciousness and bloodshed, finally achieving her execution in an especially brutal manner in 613, after winning the battle that enabled Chlothar to unite Francia under his rule. Like his father, he built up his territories by moving in after the deaths of other kings.