The church is used as a Protestant and Catholic church.
Altenberg Abbey

A former Cistercian monastery, Altenberg Abbey is a historical structure in the Bergisches Land region. The Altenberg Cathedral, the former monastery church, is now used simultaneously by both Protestant and Catholic congregations.
History+
The monastery was founded in 1133 and, thanks to its location on the Dhünn River, developed into an economic factor in the region. A decline began in the 18th century, leading to its secularization in 1803. After its dissolution, the inventory was auctioned off, and the complex was sold to a wine merchant in 1806. Later, chemists used the site for a factory, which was destroyed in 1815 after an explosion and fire. The buildings fell into disrepair, and parts of the church collapsed in 1830.
Source: Wikipedia · Licence: CC BY-SA 4.0
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 51.0547, 7.1328