He had mixed feelings about the German states, praising Prussia as a conservative society dominated by the Junkers. But he worried increasing economic growth promoted by the Zollverein (German Customs Union) was making the Prussian middle class more powerful.[31] Gobineau was critical of the Austrian Empire, writing that the House of Habsburg ruled over a mixed population of ethnic Germans, Magyars, Italians, Slavic peoples, etc., and it was inevitable such a multi-ethnic society would go into decline, while the "purely German" Prussia was destined to unify Germany.[32]