The Royal Castle in Radom was a defensive structure built within the city walls around 1350, at the time of the founding of the new town of Radom by the Polish king Casimir the Great.^[1]

Initially in the form of a single manor house (Curia Maior), the castle was expanded in the 15th century into a separate defensive structure with its own walls and towers. It became an important royal residence as well as the seat of the royal starosta.^[1] The castle also hosted significant ceremonies and state events, including the signing of the Vilnius-Radom Union with Lithuania in 1401 and the parliamentary session that passed the Nihil Novi constitution in 1505.^[1]

In 1655, the fortress was burned down by the Swedes, later rebuilt and renovated multiple times, but largely demolished in the 19th century during the dismantling of the city walls. Today, only two levels remain, including the cellars of the Curia Maior, which now houses the rectory of St. John the Baptist Church.^[1]