The miracle of San Gennaro’s blood

Q: Where are the vials containing San Gennaro’s blood?

In Naples Cathedral, in the Chapel of the Treasure of San Gennaro. Not in the catacombs, where the saint’s original tomb was instead located: see who San Gennaro was .

In short: The vials containing the blood are kept in Naples Cathedral, in the Chapel of the Treasure of San Gennaro, not in the catacombs: this is where the original tomb was located. The liquefaction traditionally occurs three times a year: the Saturday before the first Sunday in May, 19 September, and 16 December. Science has debated the phenomenon for decades without reaching a shared explanation.

The vialsNaples Cathedral

Where exactlyChapel of the Treasury

In the catacombsThe original tomb

First dateSaturday before the first Sunday in May

Second date19 September

Third date16 December

Two places that are often confused

It was the question I heard most often at the top of the climb: "where is the blood". Not here. The vials are in the Cathedral, in the Chapel of the Treasury of San Gennaro. In the catacombs was the tomb: the body was brought to these tunnels in the 5th century, and from that moment the cemetery became the city’s Christian sanctuary. Who the saint was I wrote in who San Gennaro was.

The three dates

The liquefaction traditionally repeats on the Saturday before the first Sunday in May, on 19 September, the saint’s day, and on 16 December. These are days when the Cathedral fills up and the city changes pace. What this means for those planning a visit to the catacombs I explain in when to go.

What science says

That the debate is open and there is no shared explanation. This phenomenon has been discussed for decades, with differing views and no agreement. I don’t have a theory to sell you: I report that it is a subject of discussion and leave it at that. For Neapolitans, meanwhile, it remains an act of devotion, and that is how it should be viewed when it happens.

What it has to do with the catacombs

The starting place is what matters. The Sacred Mile route exists precisely to connect the saint’s tomb, down here, to his Treasury in the Cathedral: they are the two ends of the same story, with the neighbourhood in between. What you cross underground is described in what you see underground.

Frequently asked questions

Where are the vials containing San Gennaro’s blood?

In Naples Cathedral, in the Chapel of the Treasury of San Gennaro. Not in the catacombs, where the saint’s original tomb was instead located: see who San Gennaro was.

How many times a year does the blood liquefy?

Three, according to tradition: the Saturday before the first Sunday in May, 19 September and 16 December. On how they affect your trip, see when to go.

What does science say about San Gennaro’s blood?

That the phenomenon has been debated for decades and no shared explanation exists. On this site, we report the debate and do not take a position.

Is the miracle visible in the catacombs?

No, the ritual takes place in the Cathedral. In the catacombs, you visit the two levels carved into the tuff, described in what you see underground.