Sossius was a deacon from Misenum, a significant Roman naval base, who lived during the late third and early fourth centuries. He is remembered for his martyrdom in Pozzuoli during the persecutions under Diocletian. According to tradition, he was closely associated with Januarius, the bishop of Benevento, who reportedly predicted Sossius's death through a divine sign. After being identified as a Christian, Sossius was executed by beheading alongside several companions, including Januarius, Festus, and Desiderius.