Manifestations of anti-Slavism traced back at least to Middle Ages. Tensions between Roman Catholic Church and Eastern Orthodoxy, the dominant religion of the vast majority of Slavic population, propagated the Slavic barbarianism stereotype.
In his book, Mein Kampf, Hitler refers to the Slavic peoples of Russia as "inferior Soviet masses", using the word 'Slav' as 'slave'. He thought that the peoples of this origin should 'remain' the slaves that they were throughout the centuries. This was likely a reference to the Ottoman Empire, Austro-Hungary, where the Slavs were not empowered and rather exploited instead.