At the instigation of Cardinal Oliviero Carafa, his body was finally transferred in 1497 to Naples, where he is the city's patron saint. Carafa commissioned a richly decorated crypt, the Succorpo, beneath the cathedral to properly house the reunited body and head. The "Succorpo" was finished in 1506 and is considered one of the prominent monuments of the High Renaissance in the city.
St Januarius' feast day is celebrated on September 19, in the calendar of the Catholic Church. In the Eastern Church it is celebrated on April 21. The city of Naples has more than 50 official patron saints, although its principal patron is Saint Januarius..
There is little known of the life of Januarius but local Neapolitan tradition says he was born in Benevento to a rich patrician family that traced its descent to the Caudini tribe of the Samnites. At a young age of 15, he became local priest of his parish in Benevento, which at the time was relatively pagan. When Januarius was 20, he became Bishop of Naples and befriended Juliana of Nicomedia and St.Sossius whom he met during his priestly studies as young boys. As Bishop of Naples, he performed many miracles. During the persecution of Christians by Emperor Diocletian, he hid his fellow Christians and prevented them from being caught. Unfortunately, while visiting Sossius in jail, he too was arrested. He was placed in a furnace to be cooked alive, he came out unscathed. He was pushed into the Flavian Amphitheater at Pozzuoli to be eaten by wild bears, who had not eaten in days. Yet the animals refused to eat them, instead licking their toes. Januarius was beheaded along with Sossius and his companions at Solfatara. Despite very limited information about his life and works, he is famous for the reputed miracle of the annual liquefaction of his blood, first reported in 1389. The dried blood is safely stored in small capsules in a reliquary. When these capsules are brought into the vicinity of his body on three occasions in the year, the dried blood supposedly liquefies.
Thousands of people assemble to witness this event in the cathedral of Naples. The archbishop, at the high altar amid prayers and invocations, holds up a glass phial that is said to contain the dried blood of the city’s patron saint. When the liquefaction has taken place, the archbishop holds up the phial again and demonstrates that liquefaction has taken place. The announcement of the liquefaction is greeted with a 21-gun salute at the 13th-century Castel Nuovo.
The ceremony takes place three times a year. The most famous is on the feast day on September 19, which commemorates the saint's martyrdom. On December 16, it celebrates his patronage of both Naples and of the archdiocese. The celebration on the Saturday before the first Sunday in May is for the commemoration of the reunification of his relics. The first recorded reference to the 'miracle of the blood' was in 1389. The liquefaction sometimes takes place almost immediately, but can take hours or even days.
For the Italian population of Little Italy, Manhattan, and other New Yorkers, the Feast of San Gennaro is a highlight of the year, when the saint's polychrome statue is carried through the streets and a blocks-long street fair ensues.
"The Neapolitans honor this saint as the principal patron of their city and nation, and the Lord himself has continued to honor him, by allowing many miracles to be wrought through his intercession, particularly when the frightful eruptions of Mount Vesuvius have threatened the city of Naples with utter destruction. While the relics of St. Januarius were being brought in procession towards this terrific volcano, the torrents of lava and liquid fire which it emitted have ceased, or turned their course from the city. But the most stupendous miracle, and that which is greatly celebrated in the church, is the liquefying and boiling up of this blessed martyr's blood whenever the vials are brought in sight of his head. This miracle is renewed many times in the year, in presence of all who desire to witness it; yet some heretics have endeavored to throw a doubt upon its genuineness, by frivolous and incoherent explanations; but no one can deny the effect to be miraculous, unless he be prepared to question the evidence of his senses."
John Henry Cardinal Newman also attested to the veracity of the miracle of liquefaction:
"I think it impossible to withstand the evidence which is brought for the liquefaction of the blood of St. Januarius at Naples and for the motion of the eyes in the pictures of the Madonna in the Papal States."