Of Saint Monica's famous son Saint Augustine (354-430), whom a grateful Church commemorates today, Henri Marrou once suggested that he is one of the few Christian thinkers whom non-Christians still seem to take seriously.
Historically, of course, the specific circumstances of Augustine's time, among them the collapse of classical conceptions of social order and the cosmic catastrophe suggested by the fate of the city of Rome, all created an immediate need and set the stage for Augustine's influential work. Still, something more was involved than was simply situational. If indeed Christian faith attaches certain specific requirements to one's thinking and action and imposes in the process a new form on the matter of social life, then Augustine was preeminently suited personally for his historical task. As his Confessions, for example, demonstrate, Augustine sampled most, if not all, of the available intellectual and spiritual options of his time. Having left them behind, he experienced in his own life the full force of Christian faith's distinctive demands. His Confessions clearly illustrate the transformational character of his personal experience.
In the aftermath of his baptism in 387, Augustine adopted a style of life recognizable to his contemporaries as philosophical. But already there were differences, signaling a subtle move from his previous neoplatonism. The participation of Monica in his and his companions' philosophical life (illustrated, for example, in Augustine's earliest Christian writings) immediately signified something new.
Max Weber (The Sociology of Religion) once observed that no religion ever resulted from intellectuals' chatter. Saint Monica's role in Augustine's transformation substituted for what was religiously defective amidst the admitted attractions of philosophy. She represented the alternative to be found in the authentic piety of the faith community.
Augustine, after all, was the product of a "mixed marriage." That "mixed marriage" represented the two different directions actually available to Augustine - the old Roman civic tradition, that represented the best of the past and was coming to an end, and the new tradition of Christian faith, that represented hope in the future. In Augustine's personal experience, his father personified the one and Monica the other. Monica, moreover, didn't just represent residual impressions from Augustine's childhood religious experience. She served as a bridge connecting those impressions and that childhood experience with his active adult re-immersion in the public life of his time in the context of his increasing involvement in the communal life of the Church. Hence the symbolic appropriateness of Monica's conclusion of her role in Augustine's early dialogue De beata vita (IV, 35) by her invocation of Saint Ambrose, who, perhaps more than anyone else in Augustine's experience, personally modeled Christian faith's transformative effect on classical romanitas.