The oldest period of construction development of St Catherine’s church is relatively unclear due to the absence of specific dateable finds. Specialist literature usually places the origins of the castle church before the year 1400. The exterior walls are probably all that remain of the original building in the church as we see it today. The polygonal presbytery (sanctuary) with Gothic vaulting and the entrance to the sacristy (now walled up) were built no later than the second half of the 14th century. The present form of the church interior was significantly affected by a reconstruction that can be fairly reliably dated to around 1400. The insertion of a central arcade band with two pillars transformed it to a two-aisle design. Many of the formative elements of the church have been preserved from this period – architectural decorations such as “curly leaves” and “knee consoles”, the motif of finely wrought canopies on the sides of the pillars between the aisles. The quality of the work points to a connection with the craftsmen who worked on the Stephansdom in Vienna at the end of the 14th century under the leadership of Michael Knab. The most striking of the Late Gothic works of the 1580s is the design of the vaulting in the older presbytery and the south-east oratory. The ribs of the vault have an unusual springing and intersect in the shape of swallow tails. Experts call this the “Kremnická pätka” (Kremnica springing). In the corners of the presbytery, there are unusual human and animal figures on the ribs that have been suggested to represent Christ, the donors, the prophets and evangelists and an opposing pair of devils. The church tower was already part of the medieval church. An interesting detail is a stone figural sculpture on a bracket at the southwest corner.
The Renaissance modifications relate to the reconstruction of the tower after an extensive fire in 1560. There are many symbols and dates on the corners that document the progress of reconstruction. In the interior, a Renaissance pulpit was built on the triumphal arch in the second third of the 16th century. The pulpit is finely sculpted and stands on a column with a Corinthian capital and a stone bracket supported by the figural motif of a male bust in period clothing.
The church’s current appearance mainly reflects a prestigious restoration project undertaken from 1883 to 1886. It was overseen by artist Ferenc Storno of Sopron in cooperation with his son Kálman. They attempted to recreate the church’s “Gothic” character in the spirit of historicist Romanticism. The exterior was replastered and painted with illusory stonework, while the tower was given a tall spire with turrets. The Stornos transformed the interior by installing a new organ loft at the west end, the current stone balustrade with tracery and spiral staircases. They also created a three-light window from the sacristy to the presbytery. The comprehensive renovation also included Neo-Gothic painting on the vaulting and other architectural features and the removal of older furniture. This was replaced with new Neo-Gothic items from Storno’s workshop: vibrant stained glass windows, wooden winged altarpieces decorated with gilded and painted architectural elements and panel paintings (the high altar of St Catherine of Alexandria in the presbytery, a side altar dedicated to the Virgin Mary on the left, an altar dedicated to the Holy Cross in the north chapel, the death of St Joseph on the right, an altar dedicated to St Anne in the south chapel), the canopy and wooden staircase to the pulpit, the pews, the stone sculptures on the pillars between the aisles and the facade of the south porch.
Ferenc Storno completely removed the quartet of Baroque side altars and the Early Baroque high altar whose central painting showed the Engagement of St Catherine (consecrated in 1715). Most of the statutes from this altar have survived (11 of the original 13, some of which are exhibited in the Town Hall). The interior gained two valuable additions after the demolition of the Church of the Virgin Mary on the square – a Late Gothic statue showing the Madonna standing on the crescent moon from the end of the 15th century and a Renaissance font in a chalice shape from 1561, which came from the tomb of the Kremnica medallist Christoph Füssl. The original features kept in the church include a set of memorial plaques and gravestones. The figurative and relief decoration on the memorial plaque of Wolfgang and Georg Fleisch stands out amongst them in terms of quality.
A trio of Late Gothic sculptures under the west-end gallery – St Helen (with the attribute of a cross), an unknown female saint or the Virgin Mary (no attribute) and St Elizabeth (a jug and a basket of offerings) – probably comes from the hospital church of St Elizabeth. A pair of Late Gothic statues representing St Catherine and St Barbara from the end of the 15th century stand on the south side of the nave. Their origin is not known. The free-standing stone statue of the Immaculate Conception of the Virgin Mary in the northwest corner of the nave dates from the second half of the 18th century. It is the original of a copy that stands in the yard. It is probably connected with the workshop that produced the plague column.
In 1992 a new organ was installed. It was supplied by the Varhany Krnov company and has 3,500 pipes, 3 manuals and 47 stops).