Altenberg abbey was founded in 1133 as a daughter house of Morimond Abbey and settled initially in the old castle of the Counts of Berg, Burg Berge, which the counts had left for Schloss Burg, but moved to the new purpose-built monastery in the valley of the Dhünn in 1153. It flourished sufficiently to undertake the settlement of a number of daughter houses of its own from 1143 to 1443.
In 1803 it was dissolved during the secularisation of Germany and fell into ruin. Starting in 1847 under King Frederick William IV of Prussia, a thorough restoration was carried out, and the restored church, known as the Altenberger Dom ('Altenberg Cathedral', although Altenberg was never the seat of a bishopric so this is not technically accurate), is now an interdenominational church used by both Roman Catholics and Protestants.References:
The Château des ducs de Bretagne (Castle of the Dukes of Brittany) is a large castle located in Nantes. It served as the centre of the historical province of Brittany until its separation in 1941. It was the residence of the Dukes of Brittany between the 13th and 16th centuries, subsequently becoming the Breton residence of the French Monarchy. Today the castle houses the Nantes History Museum.
The restored edifice now includes the new Nantes History Museum, installed in 32 of the castle rooms. The museum presents more than 850 objects of collection with the aid of multimedia devices. The castle and the museum try to offer a modern vision of the heritage by presenting the past, the present and the future of the city. Night-time illuminations at the castle further reinforce the revival of the site. The 500-metre round walk on the fortified ramparts provides views not just of the castle buildings and courtyards but also of the town.