Fifth-century Latin polemicist; b. probably Africa; d. probably Thrace, after 431. Marius Mercator, known only through his writings and translations, was a friend of St. augustine, to whom he sent, apparently from Rome, two anti-Pelagian tracts (now lost) in 418. He seems to have visited Constantinople and joined a Latin community of monks in Thrace. During the Nestorian troubles in 431 he composed another work against pelagius and supplied his monks with several tracts and translations in reference to both Pelagianism and nestorianism. His theological knowledge reflects that of St. cyril of alexandria and St. Augustine, and his contribution consisted in making Augustine's position known in the East while supplying the West with translations of Nestorius's sermons. His known writings are preserved in the so-called Collectio Palatina (ed. E. Schwartz, Act-Con Oec 1.5:5–70), published by a Scythian monk after 533. They include the Commonitorium super nomine Caelestii (Greek version 429, Latin 431); Commonitorium contra Pelagium, Caelestium et Julianum; the translations of four anti-Pelagian sermons of Nestorius together with the latter's Letter to Caelestius; the Refutatio symboli Theodori Mopsuestii; the Comparatio dogmatum Pauli Samosateni et Nestorii; and translations of five sermons of Nestorius on the theotokos and of excerpts made by St. Cyril from the writings of Nestorius.
Bibliography: k. baus, Lexikon für Theologie und Kirche 2 7:89. w. eltester, Paulys Realenzyklopädie der Klassischen Alter-tumswissenschaft 14.2 (1930) 1831–35. É. amann, Dictionnaire de théologie catholique 9.2:2481–85. Altaner 534–535. a. lepka, "L'Originalité des répliques de Marius Mercator à Julien d'Éclane," Revue d'histoire ecclésiastique 27 (1931) 572–579. s. prete, Mario Mercatore (Turin 1958).
[f. x. murphy]