The oldest written source about the history of Russia is the "Primary Chronicle" that was written in in the 12th century.
The author, allegedly a monk called Nestor, wrote about how the Slavs were organized in tribes that kept fighting each other. In order to stop this unorganized level of in-fighting, the Slavs were said to have invited the "Rus" to rule over them. The "Rus" were a Nordic people of Vikings (Rus means rower/oarsmen) who did indeed establish power over the Slavs then. That they were "invited" to rule over them, is most probably not true, of course, but all the other evidence fully supports a Northern people having settled in the Kievan Rus' to rule over them.
From that point on, the Western propaganda was that Slavs are subhumans whose nobility and whose ruling class was "Aryan"/Nordic. So the idea was, that everything that was good in Slavic countries came from this historical Nordic ruling class, from "the good blood" as Himmler called, while the bad came from the Slavic part of the people. Communism was seen as race war in disguise; the idea was that the Jew offers the "solution" to the Capitalist problem he himself had created - but his solution is actually a race-war-in-disguise against the Nordic people and the Nordic element in Russia. By contrast, the Nazis wanted to enslave the Slavic people but get the "good blood" for themselves.
