The Church of St. John the Baptist was founded between 1360 and 1370 by the foundation of king Casimir the Great. The first mention of the existence of the parish dates back to 1408. In the fifteenth and sixteenth centuries, chapels were added to the one-nave church. The first was the chapel of the Holy Cross, the second chapel, now called the Rosary, was founded in 1481 by the townsman of Radom Jan Warcab. In 1495 the chapel of St. Anna was added and in 1500 the chapel of Baryczkowska. Around the middle of the 15th century a tower was built, which also served as a city guard. In the years 1630-1633 from the foundation of Jan Kochanowski, the vexillifer regni, late renaissance chapel was erected. In 1752 the vault of the nave collapsed. In the early nineteenth century the church was severely damaged. Its restaurant was taken in 1817-1838. The walls of the nave were raised, which was covered with a wooden ceiling, a new roof was erected, the tower was elevated and the facade was plastered. As a result of these changes, the western façade was given neo-Gothic decor. In the years 1881-1889 the tower of the church was raised by the fifth floor. In the years 1908-1909, the church was completely rebuilt according to the design of architect Józef Dziekanski in neo-Gothic style. The changes included the extension of the nave by one bay to the west, the liquidation of outbuildings from the south and the erection of the aisle and the new sacristy.
The church was built as an orientated structure, originally with a single nave, with a slightly narrower, two-bay, three-side ended chancel located in the east. On the north side, in 1481, two bays of the chapel of the Mother of God were situated, which formed a side aisle. From the north-west side, a tower was added to the nave and the chapel in the second half of the 15th century. It was four-sided at the bottom, octagonal at the top, originally it had four floors. In the northern wall of the chancel, a sandstone portal from the beginning of the 16th century was located, leading to a square sacristy with a porch. On its floor there was a treasury to which a stone staircase led from the vestibule.
The presbytery was covered with a net vault with moulded ribs made of bricks, while the nave was also covered with a net vault, but with sandstone ribs. The nave vault was modeled on the presbytery vault. The chapel of the Mother of God originally had a flat, wooden ceiling, and there was also a small choir with stairs leading to the tower.
The present church differs from the medieval building in terms of decoration, architectural details and layout. The original row of southern chapels was rebuilt into the second aisle at the beginning of the 20th century, the original nave was also one bay shorter, it was extended to the west in 1908-1909. The northern porch with the sacristy is a structure from the beginning of the 20th century, but was built on the site of the original, medieval one. Mother of God Chapel, side aisle, western part of the nave and sacristy today have diamond vaults from the beginning of the 20th century.
Żabicki J., Leksykon zabytków architektury Mazowsza i Podlasia, Warszawa 2010.
Website fara.radom.pl, Kościół pw. św. Jana Chrzciciela w Radomiu – Fara.