The USSR had a large population of ethnic Germans, especially in the Volga German Autonomous Soviet Socialist Republic, who were distrusted and persecuted by Stalin 1928 to 1948. They were relatively well-educated, and at first, class factors played a major role, giving way after 1933 to ethnic links to the dreaded Nazi German regime as the chief criterion. Taxes escalated after the German invasion of 1941. Some settlements were permanently banished to the east of the Urals.