Cerdo was a Christian teacher, generally held to be a gnostic (Gnosis/Gnosticism), who flourished at Rome in the time of Hyginus (136–140 CE), simultaneously with Valentinus the Gnostic and Marcion and somewhat earlier than Justin Martyr. If Cerdo committed anything in writing, nothing has been preserved of his texts. According to Epiphanius of Salamis (Haer. 41.1.1) and Filastrius of Brescia (Haer. 44), he was an immigrant from Syria. This information is uncertain, however, and may simply have its origin in Irenaeus of Lyon’s report …