Saint Sossius or Sosius (Italian: Sosso, Sossio or Sosio; 275 – 305 AD) was Deacon of Misenum, an important naval base of the Roman Empire in the Bay of Naples. He was martyred along with Saint Januarius at Pozzuoli during the Diocletian Persecutions. His feast day is September 23, the date, three days after his death, on which his corpse was translated to Misenum.