The first object on the site of the castle was the parish church of the Virgin Mary, which together with the neighboring cemetery chapel of St. Michael (charnel house) was built in the 13th century, before the Mongol invasion. In the fourteenth century, a defensive wall was built around the church, and then in the first half of the fifteenth century, the defense system was expanded to include a four-sided tower and gate tower. In 1442, these fortifications did not stop Simon Rozgonyi, fighting his political opponent Ladislaus the Posthumous and his allies. As a result of these fights, the church burned down and, worse, a year later was damaged by an earthquake. In the years 1497-1515, during the reconstruction, the basilica was rebuilt into a gothic hall temple, and the fortifications were reinforced with round towers. The danger of the Turkish invasion resulted in the need for another reconstruction, which changed the fortified church into a fortress. In the years 1546-1559 the church was rebuilt into a four-wing building with an internal courtyard in the place of the old nave. These were the last major works carried out in the castle, because the baroque reconstruction in the eighteenth century concerned mainly the old gate tower.
The original church of the Virgin Mary was a three-nave romanesque basilica, and after the reconstruction from the end of the fifteenth century, it became a gothic hall church, three-nave with a narrower and shorter chancel with polygonal end. In the mid-sixteenth century, after the collapse of the vault, an internal courtyard was built, and the walling of the side aisles resulted in the creation of individual floors. The entrance to the inner courtyard led through the ground floor of the west tower. The rooms on the ground floor served as a kitchen, cells, food and weapon magazines. The floors were used as living quarters for a 50-60-person garrison crew.
The circumference of the defensive walls was erected on the plan of an irregular hexagon. It was strengthened in the first half of the fifteenth century by the eastern four-sided gate tower (also serving as a prison) called Himmelreich and the four-sided tower on the southern side. At the turn of the fifteenth and sixteenth centuries, a cylindrical tower from the north-west side was added and two semi-circular half towers opened from the side of the courtyard: north and south-west. The new towers at the ground floor level had narrow arrowslits, but already on the upper floors they were equipped with cannon shooting positions. In the perimeter of the walls, the chapel of St. Michael was earlier included. The outer zone of defense was a ditch and earth rampart, built on the west and probably on the north-east side.
Charnel of St. Michael is a typical example of a cemetery chapel from the 13th century, consisting of upper and lower part. Originally, the chapel was topped with a flat ceiling, and the lower morgue was crowned with a rib vault. From the 14th century, the upper chapel also has a rib vault. The interior was also decorated with wall paintings. Subsequent modifications were introduced in the 16th century when the charnel with the apse were included in the fortifications of the stronghold, transforming it into a low tower.
Currently, the castle complex consists of a palace building, a perimeter wall reinforced with towers and a belfry (originally a gatehouse) and a romanesque charnel. The Old Castle serves as the Slovak Mining Museum with an archaeological, craft, sculptural and historical exhibition of the region. During the summer season, theatrical performances and cultural programs take place in the castle.
Bóna M., Plaček M., Encyklopedie slovenských hradů, Praha 2007.