Cniva (Kniwa, meaning "knife") (flourished mid-3rd century CE) was the Gothic chieftain who invaded the Roman Empire in the third century CE. He successfully conquered the city of Philippopolis, present-day Bulgarian city Plovdiv, and killed the emperor Decius and his son Herennius Etruscus at the Battle of Abrittus as he was attempting to leave the Roman Empire. He was allowed to leave with his spoils and was paid tribute to stay out of the empire.