In the Kulturkampf he took an active part on the ultramontane side.
It was also the view universally taken by the German governments which supported the Kulturkampf in a greater or less degree.
Upon the outbreak of the Prussian Kulturkampf the Left had pressed the Right to introduce an Italian counterpart to the Prussian May laws, especially as the attitude of Thiers and the hostility of the French Clericals obviated the need for sparing French susceptibilities.
His policy towards all governments outside Italy was to support them wherever they represented social order; and it was with difficulty that he persuaded French Catholics to be united in defence of the republic. The German Kulturkampf was ended by his exertions.