Yet this period was by no means sterile in developments destined to produce momentous results. In Prussia especially the government continued active in organizing and consolidating the heterogeneous elements introduced into the monarchy by the settlement of 1815. The task was no easy one. There was no sense of national unity between the Catholics of the Rhine provinces, long submitted to the influence of liberal France, and the Lutheran squires of the mark of Brandenburg, the most stereotyped class in Europe; there was little in common between either and the Polish population of the province of Posen. The Prussian monarchy, the traditional champion of Protestant orthodoxy, found the new Catholic elements difficult to assimilate; and premonitory symptoms were not wanting of a revival of the secular contest between the spiritual and temporal powers which was to culminate after the promulgation of the dogma of papal infallibility (1870) in the _Kulturkampf_. These conditions formed the excuse for the continual postponement of the promised constitution. But the narrow piety of Frederick William III. was less calculated to promote the success of a benevolent despotism than the contemptuous scepticism of Frederick the Great, and a central parliament would have proved a safety valve for jarring passions which the mistaken efforts of the king to suppress, by means of royal decrees and military coercion, only served to embitter. Yet the conscientious tradition of Prussian officialism accomplished much in the way of administrative reform. The Prussian Zollverein.