[German Version] (Gk Kerdon), a Syrian (?) Gnostic who was active as a Christian teacher in Rome c. 140. According to Irenaeus of Lyon (
Haer. I, 27.2f.), Cerdo came from the school of Simon Magus and introduced Marcion, his disciple and successor in Rome, to the distinction between the good god and the just god. (He is also mentioned in Hipp.
Haer. VII, 10; 37.1f.; X, 9.1; Ps.-Tert.
Adv. omn. haer. 6; and Epiph.
Haer. 41; 42.3f.) The line of succession Simon – Cerdo – Marcion, however, is probably an anti-Marcionite fiction. A s…