The feudal castle of Sancerre was one of the strongest castles of the Middle Ages built in France. It was the seat of Counts of Sancerre. The future king Charles VII and Joan of Arc stayed at the Chateau de Sancerre, which was strategically placed on the border of the "kingdom of Bourges."
The town of Sancerre was formerly fortified. It was built under the castle, closing access to the less steep slope of the mountain. The castle and city walls were demolished in 1621.
Today only the tower, foundations, cellars or parts of walls remains of castle. The location of the old castle is now occupied by a mansion (1874) of Louis XII and a private park, owned by the Company Marnier-Lapostolle.
References:The Chapel of St. Martin is the only completely preserved Romanesque building in Vyšehrad and one of the oldest in Prague. In was built around 1100 in the eastern part of the fortified outer ward. Between 1100 and 1300, the Rotrunda was surrounded by a cemetery. The building survived the Hussite Wars and was used as the municipal prison of the Town of the Vyšehrad Hill.
During the Thirty Years’ War, it was used as gunpowder storage, from 1700 to 1750, it was renovated and reconsecrated. In 1784, the chapel was closed passed to the military management which kept using it as a warehouseand a cannon-amunition manufacturing facility. In 1841, it was meant to be demolished to give way to the construction of a new road through Vyšehrad. Eventually, only the original western entrance was walled up and replaced with a new one in the sountren side. The dilapidating Rotunda subsequently served as a shelter for the poor.