Alexander I's successor, Nicholas I was crowned King of Poland on 24 May 1829 in Warsaw, but he declined to swear to abide by the Constitution and continued to limit the independence of the Polish kingdom. Nicholas' rule promoted the idea of Official Nationality, consisting of Orthodoxy, Autocracy, and Nationality. In relation to Poles, those ideas meant assimilation: turning them into loyal Orthodox Russians. The principle of Orthodoxy was the result of the special role it played in the Russian Empire, as the Church was in fact becoming a department of state, and other religions discriminated against; for instance, Papal bulls could not be read in the Kingdom of Poland without agreement from the Russian government.