The Mother Church of Trabia, dedicated to Santa Petronilla, was commissioned by Giuseppe Lanza. The works began in 1790 and ended in 1802. The Church was initially built with a single nave, the central one. On the other hand, the two side naves built following the demolition of the walls date back to 1870. The Archpriest from Trabia Monsignor Antonino Di Matteo had the main altar built in precious white marble in 1885, the five side chapels and the marble floor of all three naves in 1887 and finally the façade in 1892. Inside the Mother Church is kept the bronze Cross found in 1830 by a young man named Carlo Bondì during the collection of sea pebbles destined to adorn the Calvary Chapel still under construction. Its discovery is believed to have caused the definitive eradication of the plague that gripped the local territories at that time. It is no coincidence that the inhabitants led the Cross in a solemn procession inside the Church in which it is still located today. The ends of the Latin cross widen into small trilobed cross heads that enclose sacred images: on the main face is Jesus Crucified surrounded by the four evangelists, while on the secondary face is the Madonna and Child. Professor Ettore Gabrici, director of the Palermo Museum at the time of the discovery, described the cross as “a valuable product of Sicilian industry with marked characteristics of fifteenth-century art”. Inside the Church there is a painting representing Santa Petronilla to whom the Church is entitled; also a painting of certain value portraying the Virgin of the Rosary, and a painting depicting St. Peter by the Spanish painter, Jusepe De Ribera known as the Spagnoletto. The remains of the Servant of God Fra’ Andrea Tonda have been kept inside the Church since 1973
