The patron saint of Pozzuoli is Saint Proculus the Martyr, commemorated by the Catholic Church on 18 October and locally on 16 November; the celebrations in his honour, however, are held on the second Sunday of May, marking the recovery and return to the town of the saint's body on 13 May 1781. In memory of that event, since 1845, at the will of Bishop Raffaele Purpo, the celebrations have been concentrated in this period of the year.
The basilica of San Procolo, the town's main Catholic place of worship and seat of the diocese of the same name, stands atop the Rione Terra: it is a very ancient complex, probably arising in the Greek or Samnite period as the town's Capitolium, before being converted into a Christian church and dedicated to the Puteolan martyr between the late 5th and early 6th centuries. Among the martyrs of Roman Pozzuoli, then called Puteoli, sources also record Artema, Acuzio, Eutyches, Januarius, Sosso, Festus and Desiderio: it is precisely to Saint Januarius, beheaded near today's Solfatara sanctuary, that local tradition attributes the liquefaction of the blood kept on the stone of his execution.
