The basilica was built around 1580-1600 in honor of the Madonna delle Grazie and became the famous "Sanctuary of Santa Filomena" only years later.

The founder of this sanctuary was Francesco De Lucia, a humble priest born in Mugnano del Cardinale, from a barber, in 1772. After his ascension to the priesthood in 1796 he taught literature and philosophy first in the Casa D'Illiceto, then in Naples. In 1805 he went to Rome to accompany Mons. Bartolomeo De Cesare, bishop of Potenza. On this occasion, thanks to the Monsignor, he obtained from the Pontiff a sacred body, with an ampoule containing blood, which he believed to be of the Virgin and Martyr Filumena. This is because in the niche were found three brick tablets on which the following words were read: LUMENA | PAX TE | CVM FI, with the symbols of the lily, the palm and the anchor, tablets that were later sold on 11 July 1827 to the rector De Lucia through Pope Leo XII.

In possession of this treasure De Lucia returned with it to Naples, where he had the sacred bones covered with the simulacrum of a girl and with clothes donated by a Lady Angelarosa Torres. Back in Mugnano, the parish priest D. Antonio Ippolito wanted this relic in the parish church, but De Lucia preferred to deliver it to the church of the Grazie, where it was never removed. Shortly afterwards he donated it with a public deed to the Municipality, in order to have in exchange the appointment of Custos, and then also that of Rector for life of that Church, of municipal patronage. From that day the cult of St. Filomena spread throughout Italy, and from Italy all over the world.