However, there are many examples of large multicultural empires that have existed throughout time where the religion of the state was not imposed on subjected regions.
For example, in medieval Europe Jewish people suffered various degrees of official and unofficial discrimination; during the same period in Islamic states, non-Muslims or dhimmi were legally inferior to Muslims but in theory accorded certain protections.
In Europe, the 1648 Treaty of Westphalia institutionalized the principle of cuius regio, eius religio—that rulers of a state had the right to determine the religion of its subjects.
Several of the Thirteen Colonies were confessional states, although of different denominations, before the American Revolution; Connecticut remained one until 1818.
Russia is formally secular but its government strongly promotes and relies on Orthodox Christianity and its values.