martyrdom · 305 · Puteoli
Januarius was bishop of Benevento and was killed in the Great Persecution, at Puteoli — modern Pozzuoli — with several companions, having gone to visit a deacon in prison. The tradition that they were first thrown to the beasts and that the beasts would not touch them belongs to the later passion. The cult is old and well attested at Naples, where his relics were brought and where he has been the patron ever since; he is one of the very few saints whose city still treats him as a functioning civic institution. The blood is the part everyone knows and it needs stating precisely. Two sealed phials of a dark solid, kept in Naples cathedral, are exposed three times a year, and on most of those occasions the contents become liquid. The first record of this happening is from 1389 — a thousand years after his death — and the church has never defined it as miraculous, permitting the devotion without ruling on the cause. Chemists have produced thixotropic gels that behave the same way with materials available in the fourteenth century, and the phials have never been opened. This dataset records the cult, the date of the first report, and the fact that it is unexplained rather than explained.
What is actually known, and what is the blood?
A bishop killed at Pozzuoli, and a phenomenon first recorded a thousand years later.