In the early Viking Age, no national kings existed.As the Viking Age progressed, power began to centralize in the hands of a few strong leaders, who became the kings of Sweden, Norway and Denmark beginning in the 9th century.There were three broad social classes: the nobles or jarls, the middle class or karls and the slaves or thralls.He might then become among the medieval freemen, but he probably wouldn't be able to improve his circumstances much from there.