The Archdiocese of Turku is the oldest diocese in Finland. Medieval bishops of the Catholic Church were also de facto secular leaders of the country until the end of the 13th century. After the Reformation in Scandinavia, Lutheran bishops became state officials. When Finland became a separate grand duchy, the then Bishop of Turku was designated as an Archbishop in 1817. Since 1868, the Archbishops of Turku and Finland have been considered primates of the Evangelical Lutheran Church of Finland.