Built in the mid-16th century to meet new urban needs, it was named Santa Maria la Nova to distinguish it from the previous Mother Church, Santa Maria la Vetere.
Already in the late 16th century, the large church was functional, although the official date of the end of construction is 1620. In 1844, Caltanissetta became a bishopric, and the Mother Church was given the title of Cathedral. Part of the façade and the internal vault, destroyed by American bombings in 1943, were rebuilt immediately after the war, and during that time, the transept and dome were also constructed.
The white façade, simple and austere, is characterized by two superimposed orders: in the lower one, divided by pilasters, there are three entrance portals; the upper order consists of a central body surmounted by a triangular pediment and two side bell towers.
The structure has a basilica layout with three naves, divided by massive pillars, and an impressive vaulted ceiling. The entire vault was frescoed in 1720 by Guglielmo Borremans, a Flemish painter active in Caltanissetta in the 18th century, using trompe l'oeil technique. The painter creates the illusion that five large windows open onto the ceiling, allowing a view of the sky and scenes of paradise. Around them is a long series of saints and some episodes from the lives of St. Peter and St. Paul. The vault is therefore richly and completely frescoed, full of light and life.
By the same author is the altarpiece dedicated to the Virgin, painted with warmer and less bright colors compared to the vault frescoes. The decorations on the archways of the pillars, depicting scenes from the Bible, can instead be attributed to Borremans' school.
Many chapels along the side aisles contain valuable works of art: a 17th-century crucifix attributed to Friar Umile da Petralia; the Immaculate Conception, a wooden statue clad in silver, made by Sicilian silversmiths of the 18th century; the large painting of Our Lady of Mount Carmel, the work of Filippo Paladini from the early 1600s; the highly revered 17th-century statue of St. Michael, protector of the city, the work of Stefano Livolsi; and some large canvases by Vincenzo Roggeri, a painter from Caltanissetta in the 1600s.
On a side wall of the apse is the large 17th-century organ, built by craftsmen from Palermo and decorated with seven painted panels by Vincenzo Roggeri, depicting seven archangels. In recent decades, the vault frescoes of the Cathedral have undergone valuable restoration, and a new altar, episcopal chair, and large suspended cross at the center of the presbytery have been installed. Also worth seeing is the evocative Chapel of the Blessed Sacrament, by a modern author, housing a beautiful gilded silver tabernacle, a gift from Pope Leo XIII to the city on the occasion of the 1900 Jubilee. Recently, the gate closing off the churchyard, removed after the war, has also been rebuilt.