Saint John IV called the Peacemaker and known in Italian as Giovanni d'Acquarola, was the Bishop of Naples from an unknown date until his death. He is one of the patron saint

Patron saint

A patron saint is a saint who is regarded as the intercessor and advocate in heaven of a nation, place, craft, activity, class, clan, family, or person...

s of Naples and his feast day is 22 June. He had the relics of Aspren

Aspren

Aspren or Asprenas was a 1st century Christian saint and venerated as the first Bishop of Naples.Aspren lived at the end of the 1st century and in the early 2nd century, as confirmed by archaeological studies regarding the early Neapolitan Church as well as the fact that "Aspren" was a common name...

 translated to the church of Santa Restituta

Santa Restituta

Santa Restituta is a church in Naples, southern Italy, dedicated to Saint Restituta.It is the original 6th-century paleo-Christian church on the site where the Cathedral of Naples now stands, and was rebuilt and incorporated into the cathedral when it built in the 13th century.Santa Restituta has a...

 in Naples. He also assisted Duke Andrew II

Andrew II of Naples

Andrew II was the duke of Naples from 834 to 840. During his reign, he was constantly at war with the Lombards and he allowed Gaeta, his vassal, to move towards independence under its own consuls....

 in negotiating the Pactum Sicardi

Pactum Sicardi

The Pactum Sicardi was a treaty signed on 4 July 836 between the Greek Duchy of Naples, including its satellite city-states of Sorrento and Amalfi, represented by Bishop John IV and Duke Andrew II, and the Lombard Prince of Benevento, Sicard...

, an economic treaty, with Sicard

Sicard of Benevento

Sicard was the Prince of Benevento from 832. He was the last prince of a united Benevento which covered most of the Mezzogiorno. On his death, the principality descended into civil war which split it permanently...

, Prince of Benevento.