The Gevangenpoort (Prisoner's Gate) is a former gate and medieval prison on the Buitenhof. From 1420 until 1828, the prison was used for housing people who had committed serious crimes while they awaited sentencing.
Its most famous prisoner was Cornelis de Witt, who was held on the charge of plotting the murder of the stadtholder. He was lynched together with his brother Johan on 20 August 1672 on the square in front of the building.
In 1882, the Gevangenpoort became a prison museum. The 'gate' function was lost in 1923 when the houses adjoining the Hofvijver were taken down to build the street that now allows busy traffic to run by it.
Since 2010, museum visitors can view the restored art gallery that can be reached through a special staircase that connects the two buildings. The collection which hangs here is a modern reconstruction of the original 1774 art cabinet that was situated upstairs above the fencing school. The paintings are again upstairs, hanging crowded together on the walls in the style of the late 18th-century. In 1822 the collection was moved to the Mauritshuis which remains the formal owner of the paintings on display. During restoration activities, highlights of the permanent Mauritshuis collection have been temporarily displayed in the gallery.
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.