Aggsbach Charterhouse is a former Carthusian monastery in Aggsbach Dorf. The monastery was founded in 1380 by Heidenreich von Maissau. It was dissolved in 1782 in the reforms of Emperor Joseph II. The premises were mostly converted for use as a castle, except for a few portions which were incorporated into the parish priest's farm. The monks' cells and the cloister were demolished. The Carthusian church, with the addition of a tower, remains as the parish church.
References:Château de Niort is a medieval castle in the French town of Niort. It consists of two square towers, linked by a 15th-century building and dominates the Sèvre Niortaise valley.
The two donjons are the only remaining part of the castle. The castle was started by Henry II Plantagenet in the 12th century and completed by Richard the Lionheart. It was defended by a rectangular curtain wall and was damaged during the Wars of Religion. In the 18th century, the castle served as a prison.
The present keeps were the central point of a massive fortress. The southern keep is 28m tall, reinforced with turrets. The northern tower is slightly shorter at 23m. Both are flanked with circular turrets at the corners as well as semicircular buttresses. Each of the towers has a spiral staircase serving the upper floors. The Romanesque architecture is of a high quality with the dressed stones closely jointed.