Controversy persists over whether the Rus' were Varangians (Vikings) or Slavs. This uncertainty is due largely to a paucity of contemporary sources. Attempts to address this question instead rely on archaeological evidence, the accounts of foreign observers, legends and literature from centuries later. To some extent the controversy is related to the foundation myths of modern states in the region. According to the "Normanist" view, the Rus' were Scandinavians, while Russian and Ukrainian nationalist historians generally argue that the Rus' were themselves Slavs. Normanist theories focus on the earliest written source for the East Slavs, the Russian Primary Chronicle, although even this account was not produced until the 12th century. Nationalist accounts have suggested that the Rus' were present before the arrival of the Varangians, noting that only a handful of Scandinavian words can be found in modern Russian and that Scandinavian names in the early chronicles were soon replaced by Slavic names. Nevertheless, archaeological evidence from the area suggests that a Scandinavian population was present during the 10th century at the latest. On balance, it seems likely that the Rus' proper were a small minority of Scandinavians who formed an elite ruling class, while the great majority of their subjects were Slavs. Considering the linguistic arguments mounted by nationalist scholars, if the proto-Rus' were Scandinavians, they must have quickly become nativized, adopting Slavic languages and other cultural practices.
Is there an answer to this question (If it cannot be answered, say "unanswerable"): What certainty was largely to contemporary sources/
unanswerable