Kulturkampf was one of the largest attacks on Christianity during the 1870's. The Catholic Church in Germany had been pressuring for the freedom of the churches, as was outlined in the newly-approved German constitution. At first, Otto von Bismark left the issue to the individual state in the German Confederation, but he eventually came to the opinion that the Roman Catholic Church was a threat to the German Empire's political unity. To reduce the church's power, Bismark used legislative measures that took control of education away from the Catholics.
In 1873, Otto von Bismark created the May Laws. These laws required all priests to be educated in German schools and universities. Also, potential clergymen had to pass several state-administered examinations. Finally, the state had the power to veto the appointments of priests. When the church complained and broke the May Laws, Otto von Bismark used the police. By 1876, all of the Catholic bishops in Germany had either been arrested or exiled.
Eventually, the Christians fought back. The Catholics had found allies who helped them avoid persecution. Bismark finally realized that his "Cultural Struggle" had taken education away from the church at the price of alienating a good proportion of the population. By the end of the 1870's, the chancellor abandoned Kulturkampf. The attacks were probably the largest mistake of Otto von Bismark's political career.
The Western Heritage. Donald Kagen. 1998