ABSTRACT
The difference in tone between Cyril’s writings against the Arians and those against Nestorius is striking. The latter are altogether more vehement and expressed in much more personal terms. With the appearance of Nestorius, Cyril felt himself challenged at the vital core of his faith, and not by a heretic on the margins of the catholic Church but by the bishop of the imperial city itself whose views inevitably commanded a wide audience. The fight against the enemy within was to call for all the resources that Cyril could muster.
