The church of St Just is medieval. There are no remains of the early medieval church and only part of the chancel remains from the church built in 1334 which was dedicated on 13 July 1336 by the Bishop of Exeter, John Grandisson. The current building dates from the 15th-century. In 1355 the church was given to Glasney College by Sir John de Beaupre together with the church lands of Lafrowda. Medieval chapels in the parish included a chapel of St Helen at Cape Cornwall and a chapel of St Michael on Chapel Carn Brea.
The church is large and built of regular granite blocks. Both the body of the church and the tower are of the 15th-century and the tower is of three stages. The aisles are built to the same design with alternating windows of two different patterns. The arcades have limestone piers. The font is modern but has been described as 14th-century in date. Two medieval wall paintings remain but they are both heavily restored; one portrays St George and the other a warning to breakers of the Sabbath.
The Selus Stone is thought to date from the late 5th or early 6th-centuries. It bears the Latin inscription Selus Ic Iacet (Selus lies here). This is thought to refer to Salomon of Cornwall, otherwise known as Saint Selevan.
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.