Marius Mercator (born probably in Northern Africa about 390; died shortly after 451) was a Latin Christian ecclesiastical writer best known for his advocacy of Augustinian theology during the Pelagian controversy.
His works, mostly translations and compilations of excerpts from heretical as well as orthodox Greek theological writers, were edited by Jean Garnier (Paris, 1673), reprinted in Migne (Patrologia Latina, XLVIII, Paris, 1846). They were also edited by Baluze (Paris, 1684), reprinted with corrections in Andrea Gallandi, "Bibliotheca veterum Patrum", VIII (Venice, 1772), 613-738. His treatises "Commonitorium super nomine Cælestii", and "Commonitorium adversus hæresim Pelagii et Cælestii vel etiam scripta Juliani" are against the Pelagians. The former effected the expulsion of Julian of Eclanum and Cælestius from Constantinople and their condemnation at Ephesus in 431.
- Ep. ad. M.M., no. 193.
- In Migne, loc. cit., 63-108.
- In Migne, loc. cit., 109-172.
- Migne, loc. cit., 773.
- Migne, loc. cit., 907-932.
- Marius Mercator featured on the 1000 Belgian Franc banknote from 1965.[The banknote does not show the 5th-century Marius Mercator but the 16th-century cartographer Gerard Mercator (--> Mercator Projection).]