Construction of the Porrentruy castle took place between the mid-13th century and the beginning of the 18th century. The oldest part is the thirteenth century Réfous Tower. 14th century ramparts survive on the western and northern sides.
During the reign of Prince-Bishop Jacob-Christoph Blarer of Wartensee, the castle underwent an extensive period of reconstruction by the architect Nicolas Frick around 1588. In 1697, it suffered a huge fire. The courtyard is enclosed to the south by the long Princess Christina Wing, which was named in memory of visits made by Christina of Saxony, the aunt of Louis XVI and Abbess of Remiremont from 1773 to 1775.
Since 1271 belonging to the bishopric of Basel, the castle served as exile residence of the prince-bishops of Basel from 1527 until 1792. The bishops had been exiled from Basel during the Swiss Reformation in 1529, whereas they were able to keep most of their territories outside the city.
Today, the castle is the seat of the judicial authorities of the Republic and Canton of the Jura. The building’s interior is not open to the public at weekends.References:
Prunn Castle is perched on an almost vertical Jurassic outcrop high above the Altmühl river valley south-west of Regensburg. Its impressive appearance from a distance is matched by the views from the castle of the surrounding Altmühltal countryside.
Lords of Prunn were first mentioned in 1037, and they will have certainly chosen the site because of its favourable position on several transportation routes. The castle itself dates from around 1200, a time when many castles were being built. The Danube region centring around Kelheim became very important in this period under the Bavarian duke Ludwig I. One of the oldest parts of the castle is the 31-metre keep.
In 1288, Duke Ludwig of Bavaria acquired the castle from the lords of Prunn-Laaber. In the first half of the 14th century the duke then invested the Fraunberg vom Haag family with the castle.