When you pray with a Saint Januarius rosary do you know its significance? Have you ever heard of the feast of San Gennaro? This is the feast of Saint Januarius as he was originally called. Saint Januarius was the bishop of Naples, Italy. At an early age, he was called to the faith and spent much of his life evangelizing and protecting other Christians from the persecution of the Roman Emporer Diocletian. Saint Janarius was martyred for his Christian beliefs and his many conversions to Christianity. His feast day is September 19th. He is the patron saint of Naples, Italy, blood banks and against volcanic eruptions.