The publication of Michel Foucault’s Les Aveux de la chair (History of Sexuality, Volume 4: Confessions of the Flesh) thirty-four years after his death highlights and complicates the relevance of Christian texts—notably from the second through fifth centuries—to Foucault’s forms of critical analysis between 1974 and 1984, as his interests migrate from monastic disciplines to pastoral power to governmentality to the care of the self. What begins as suspicion towards confession as a tool of Catholic power anticipating modern psychoanalysis becomes a critical genealogy of subjectivity from western antiquity to modernity. To frame Foucault’s dynamic engagement with forms of Christianity, I establish three stages over his last decade as he moves from diagnosing mechanisms of power to analyzing ethics as care of the self. Tracing Foucault’s textual and critical developments enables better analysis of Confessions of the Flesh and affirms methodological possibilities in the study of religion today.