With the Reformation in Denmark in 1536, Lutheran Christianity was established as the state religion. For the next century, in a time when religious wars swept Europe, harsh persecution of other faiths followed (Lutheran orthodoxy). Exceptions were granted only to foreign diplomats. For at least a period in the 16th century, small circles of clandestine Catholicism prevailed. From 1683, Roman Catholic, Reformed and Jewish congregations were allowed in the new town of Fredericia, the latter two also in Copenhagen. Non-Lutherans were also allowed in Friedrichstadt and on Nordstrand in Slesvig and in Glückstadt in Holstein. With the constitution of 1849, freedom of religion was introduced in Denmark, but Lutheranism remained the state church.