The Łęczyca Royal Castle was erected by Casimir III the Great as a fortification during 1357–1370. Immediately after its completion, the Castle became a residence of king, and then was the seat of the governor of Łęczyca. In 1406 it was burned by the Teutonic Knights and rebuilt in the following years to serve as a place of a conference in 1409, where decisions were taken in connection with the approaching war with the Order. After the Battle of Grunwald many of the Teutonic Knights were incarcerated here. In subsequent years, four diets were held here (1420, 1448, 1454 and 1462), and the castle became the seat of the king Casimir IV Jagiellon during another war with the Order (1454-1466).
After a great fire in the second half of the 15th century the castle remained in ruins till the early 1560s. Then, in 1563–1565, Jan Lutomirski, Grand Treasurer of the Crown completely rebuilt the castle. The cost of the entire project amounted to nearly 3,000 florins, derived from the royal treasury. The disasters that struck the stronghold in the first half of the 17th century helped the Swedish General Robert Douglas, Count of Skenninge to take the castle, which was defended by starosta Jakub Olbrycht Szczawiński, during the Deluge in 1655. The destruction was completed in 1707 during another Swedish occupation.
Over the next years local residents used the remains of the castle as a source of building materials. After the World War II, the castle became the seat of the scout troop, and in 1964 reconstruction started.
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.