The Altenberger Dom is the former abbey church of Altenberg Abbey which was built from 1259 in Gothic style by Cistercians. Listed as a cultural heritage, it is located in Altenberg, now part of Odenthal in the Rheinisch-Bergischer Kreis, North Rhine-Westphalia, Germany. Until 1511, the church was the burial site of counts and dukes of Berg and the dukes of Jülich-Berg.
Badly damaged after the monastery was dissolved in 1803 due to the secularisation of Germany, the church was rebuilt with support from Friedrich Wilhelm IV of Prussia, who decreed in 1857 that it was to serve as a parish church simultaneously for a Catholic and a Protestant parish.
Wikipedia https://en.wikipedia.org/wiki/Altenberger_Dom
Coordinates 51°3'18.059" N 7°7'59.974" E