To Cornelius, Concerning Fortunatus and Felicissimus, or Against the Heretics.
Argument.— Cyprian Chiefly Warns Cornelius in This Letter Not to Hear the Calumnies of Felicissimus and Fortunatus Against Him, and Not to Be Frightened by Their Threats, But to Be of a Brave Spirit, as Becomes God's Priests in Opposition to Heretics; Namely, Those Who, After the Custom Prevailing Among Heretics, Began Their Heresy and Schisms with the Contempt of One Bishop in the Church.
Source: The Epistles of Cyprian (New Advent)