This course will involve close and critical engagement with key primary texts on the Christian doctrine of the Holy Trinity. Readings will be organized chronologically and will involve such major classic theologians as Tertullian, Origen, Hilary of Poitiers, Augustine, Aquinas, Richard of St. Victor, and Gregory Palamas. Theologians from the Reformation and Post-Reformation era will include John Calvin, John Owen, and Friedrich Schleiermacher, among others. Modern post-Barthian issues in trinitarian theology will also be discussed, with a particular focus on Karl Barth himself, the immanent-economic axis (Rahner et al.), the varieties of social trinitarianism, and recent feminist and queer engagements with the Trinity (e.g., LaCugna, Coakley, Tonstad). A major aim of the class will be for students to wrestle with the biblical, dogmatic, and practical demands of the doctrine according to the framework and material claims established by the Nicene-Constantinopolitan settlement of the fourth century.