Time and again religious beliefs have substantially determined the politics of the country. The missionary work among the "pagan" Old Prussians gave the Teutonic Order cause for war and conquest. As the first Protestant country, the Duchy of Prussia attracted Protestants from many countries. Later, a tolerant attitude was adopted in order to win as many settlers as possible.
"East Prussia" was never a religiously uniform country. Even after the forced baptism of the Old Prussians, some of their traditions were preserved. After the introduction of the Reformation in the Duchy of Prussia, Warmia (Ermland), which belonged to Poland, remained Roman Catholic.
But the Protestants were also divided. Strife and unrest arose when in 1614 the sovereigns changed to the Reformed confession (Calvinism). The population of Prussia was allowed to retain its Lutheran form of Protestantism. This was a deviation from the rule that the ruler's faith was also to dictate the religion of the ruled (cuius regio, eius religio). Later non-Protestant inhabitants such as Jews, Mennonites and Philippians (Old Believers of the Orthodox Church) from Russia also benefitted to varying degrees from this tolerance.
Illustration:
The cathedral of Königsberg
Built between 1330 and 1380 the cathedral stands on the Pregel island of Kneiphof in the very centre of Königsberg (today’s Kaliningrad). From 1525 it was the main Protestant church. In 1944 the cathedral was severely damaged by air raids but was never demolished because of the grave of Immanuel Kant. After 1990 it was rebuilt and reopened in 1998. It houses exhibitions on Kant and the city's history but is also used for concerts and church services.