townsfolk and those living in the surrounding area becoming Catholic once again. As of 1626, there was once more a monastery in town, this time a Jesuit one. After passing to Prussia in 1815, the union between Lutheran and Reformed churches was introduced in Siegen, as it was throughout Prussia, but the town's parishes kept their Reformed emphasis. As part of the Westphalian Provincial Church (now the Church of Westphalia), Siegen became the seat of a Superintendency. A similar entity still exists in Siegen, known as the Kirchenkreis, or church district, to which all the city's parishes nowadays belong, unless they are Free Church parishes. This church district encompasses the whole of South Westphalia all the way to Olpe. The town's Catholics, even after the Reformation, still belonged to the Archbishopric of Mainz. With the restructuring of the Catholic Church early in the 19th century, Siegen was assigned to the Archbishopric of Paderborn and became the seat of a district synod, today a deaconry, to which all the district's Catholic parishes belong. Paderborn was raised to Archbishopric in 1929. Besides the Roman Catholic Church, Siegen also has a Greek Orthodox parish and a Romanian Orthodox parish. Moreover, there are various free churches established in Siegen, among them several Evangelical Free Church parishes (Baptists), an Evangelical-Methodist Church, an Independent Evangelical-Lutheran Church (SELK), a Seventh-day Adventist parish, several Free Evangelical parishes (FeG), the Achenbach Christian Community, the Christian Assembly, Calvary Chapel and the Siegen-Meiswinkel Mission Community. Further religious communities in Siegen are the Church of Jesus Christ of Latter-day Saints, the New Apostolic Church, the Jehovah's Witnesses, an Original Christianity community and Baháʼí. Moreover, owing to a great number of Turkish and Arab migrants in Siegen, the Muslim community is also very much in evidence there and there are several mosques in Siegen run by Turkish, Arab and Albanian communities. There are said to be more than 15,000 Muslims out of Siegen's total population. Municipal reform The following communities and rural areas have been amalgamated with Siegen: 1902 and 1912: parts of Buschgotthardshütten 1934: parts of Achenbach 1937: parts of Achenbach and Buschgotthardshütten 1966: Trupbach, Seelbach, Breitenbach, Bürbach, Kaan-Marienborn and Volnsberg 1969: Feuersbach 1974: towns of Hüttental and Eiserfeld Population development In 1897, Siegen had 20,000 inhabitants. By 1939, this figure had doubled to 40,000. In the World War II, the town lost roughly 30% of its inhabitants (12,000). The population had