Tertullian – Against the Valentinians
Adversus Valentinianos or Against the Valentinians is a famous refutation of Valentinianism by Tertullian. Valentinianism was a gnostic movement founded by Valentinus (an early Roman gnostic theologian) around 200 AD. It began as a Christian movement, morphed into something else entirely (possibly out of frustration when Valentinus failed his bid for a bishop of Rome),