Turks were often used synonymously with Muslims, as a prayer book of Caspar Melissander from 1609 reads, "Sweet Lord Jesus Christ, keep us from the Turk, the Tattar, the Pope and all sects." Decrees during the 17th century eventually made practicing Islam illegal, as well as any other religion outside of the Church of Sweden. In 1734, membership in the Church of Sweden was established as a precondition for citizenship, and any non-Lutheran could be banned from entry into the country.[10]