Januarius, Bishop of Naples, is a martyr saint of the Roman Catholic and the Eastern Orthodox Churches. While no contemporary sources on his life are preserved, later sources and legends claim that he died during the Diocletianic Persecution, which ended with Diocletian's retirement in 305.
Januarius is the patron saint of Naples, where the faithful gather three times a year in Naples Cathedral to witness the alleged liquefaction of what is claimed to be a sample of his blood kept in a sealed glass ampoule.
Read more about Januarius: Biography, Relics, Celebrations, The Blood Miracle, Museum of The Treasure of St. Januarius, Friedrich Nietzsche