14. HAERETICUS. Isidore of Seville, in speaking of Idacius Clarus, and Sulpicius Severus, in his Historia Sacra
(2.61), mention Marcus, a native of Memphis, as being eminently skilled in magic, a Manichaean, or perhaps personally a disciple of Manes, and the teacher of the persecuted heresiarch Priscillian.
He is noticed here as having been by Jerome and others confounded with the earlier heresiarch of the same name. [No. 13.] (Isidor. Hispal. De Script. Eccles.
100.2; Sulp. Sever. l.c.