Catechetical Resources of the Early Church

Clemens Alexandrinus, Paedagogus | Ante-Nicene Fathers 2: Fathers of the Second Century: Hermas, Tatian, Athenagoras, Theophilus, and Clement of Alexandria (Entire)

The Enchiridion 122.33 | Nicene and Post-Nicene Fathers 1.3: St. Augustin: On the Holy Trinity, Doctrinal Treatises, Moral Treatises

On Christian Doctrine | Nicene and Post-Nicene Fathers 1.2: St. Augustin’s City of God and Christian Doctrine

Page lix | Nicene and Post-Nicene Fathers 2.7: S. Cyril of Jerusalem, S. Gregory Nazianzen

Athanasius, On the Incarnation of the Word | Nicene and Post-Nicene Fathers 2.4: St. Athanasius: Select Works and Letters

The Great Catechism | Nicene and Post-Nicene Fathers 2.5: Gregory of Nyssa: Dogmatic Treatises, etc.
Conferences 1 | Nicene and Post-Nicene Fathers 2.11: Sulpitius Severus, Vincent of Lérins, John Cassian

On the Mysteries | Nicene and Post-Nicene Fathers 2.10: St. Ambrose: Select Works and Letters

An Exact Exposition of the Orthodox Faith | Nicene and Post-Nicene Fathers 2.9: St. Hilary of Poitiers, John of Damascus