John III, the sixty-first Pope was the pontiff for a relatively long period of thirteen years, however information about his pontificate remains scarce.

John III, whose birth name was Catelinus, was elected as the sixty-first pope on July 17th, AD 561. He was chosen as the successor of Pope Pelagius I, with the support of the Emperor Justinian, and Narses, a general in Italy.

Within seven years into his papacy, Italy was invaded and largely controlled by the Lombards, a Germanic tribe living in the North of Italy. The Lombards reintroduced Arian belief to Italy, which was largely eradicated prior to the Pope’s reign.

This situation led to the settlement of the schism that had arisen between Rome and the Churches of the Western Church during the reign of Pope Pelagius I and led to their reconciliation with Rome and the Holy See.

Following the death of Emperor Justinian in AD565, Rome's relations with the ecclesiastical community in North Africa became stronger.

Meanwhile, the Lombards ceased and took over the city of Milan. The new bishop of Milan, realizing that it was politically prudent to restore union with Rome, reconciled with them in AD 573. The Diocese of Aquileia refused to be united with the throne of Peter.

When the Lombards moved from Rome to the southern part of Italy, Pope John III requested the Exarch of Italy, Narses residing in Naples, to return to Rome and resolve the crisis caused by the invasion of the Lombards.

The Romans however were dissatisfied with the return of the unpopular exarch to Rome. Moreover, the Exarch's lack of acceptance by others tainted the papacy itself.

In order to avoid further confrontation between Narses and the Romans, Pope John III withdrew himself from the city of Rome and remained in Rome until Narses' death.

Pope John III, returned to the Lateran Palace but passed away about a year later, ending his papacy.