By the 18th century, the German people began to think of themselves as a distinct nationality. The Congress of Vienna consolidated the German states in 38 called the German Confederation. The Zollverein was a custom and tariff formed by Prussia in 1834. It said that there was to be no tariffs on goods trading to and from the German states with each other. There was economic unity before there was political unity. But, there was a difference in many German people, religion, economy. And Austia opposed the union. Supressed liberal and nationalistic ideas by censorship and strict supervision of education. Failed campaign for unity in 1848 with the Frankfurt Assembly. Leaders such as Bismarck, William I, King of Prussia, and General von Moltke led the cause for German unification. They created a strong Prussian military, eliminated Austria's influence through the Austro-Prussian War in 1866. The Franco-Prussian War unified the southern and northern states.