Notes on contributors; Acknowledgments; Note on the texts and translations; Series introduction; Introduction; Part I. The Emergence of Christian Theology (150-300): 1. Ptolemy, Letter to Flora translated by Bradley K. Storin; 2. The Gospel of Truth translated by Ellen Muehlberger; 3. Irenaeus of Lyons, Against Heresies 1.21.1-2, 2.28.1-9 and 4.20.1-8 translated by Anthony Briggman; 4. Tertullian, Against Marcion 1.2-5 and 1.22-27 translated by Mark DelCogliano; 5. Hippolytus, Against Noetus 1-11 and 14-17 translated by Andrew Radde-Gallwitz; 6. Origen of Alexandria, On First Principles, Preface and 1.1-3 translated by Bradley K. Storin; Part II. Creeds and Controversies (300-400): 7. Arius, Letters to Eusebius of Nicomedia and Alexander of Alexandria translated by Mark DelCogliano; 8. Creed of the Council of Nicaea (325) translated by Mark DelCogliano; 9. Eusebius of Caesarea, On Ecclesiastical Theology 2.1-7 translated by Mark DelCogliano; 10. Hilary of Poitiers, On the Trinity 8.19-26 and 41 translated by Mark DelCogliano; 11. Basil of Ancyra, The Synodal Letter of the Council of Ancyra translated by Jeffrey Steenson; 12. Athanasius of Alexandria, On the Synods at Ariminum and Seleucia translated by Andrew Radde-Gallwitz; 13. Ephrem, Hymns on the Faith 40, 73-75 translated by Ellen Muehlberger; 14. Ephrem, Commentary on the Gospel 1.2-8 translated by Matthew Crawford; 15. Basil of Caesarea, Letters 159 and 236.6 translated by Mark DelCogliano; 16. Ambrose of Milan, On the Faith 1 translated by Mark DelCogliano; 17. Creed of the Council of Constantinople (381) translated by Mark DelCogliano; 18. Gregory of Nyssa, On the Holy Spirit against the Macedonian Spirit-Fighters translated by Andrew Radde-Gallwitz; 19. Gregory of Nazianzus, Poems 1.1.1-3 translated by Bradley K. Storin; 20. Eunomius of Cyzicus, The Confession of Faith translated by Mark DelCogliano; Part III. Doctrinal Inheritance and Philosophical Exploration (400-c.570): 21. Augustine of Hippo, Sermon 52 translated by Mark DelCogliano; 22. Cyril of Alexandria, Five Tomes against Nestorius 4.1-2 Translated by Matthew Crawford; 23. Pseudo-Dionysius, On the Mystical Theology to Timothy translated by Andrew Radde-Gallwitz; 24. Boethius, On the Holy Trinity Translated by Andrew Radde-Gallwitz; 25. John Philoponus, Fragments on the Trinity translated by Andrew Radde-Gallwitz; Suggestions for further reading; Scriptural index.