Some scholars, chiefly in Germany, distinguish patrologia from patristica. Josef Fessler, for instance, defines patrologia as the science which provides all that is necessary for the using of the works of the Fathers, dealing, therefore, with their authority, the criteria for judging their genuineness, the difficulties to be met within them, and the rules for their use. But Fessler's own "Institutiones Patrologi" has a larger range, as have similar works entitled Patrologies, for example that of Otto Bardenhewer (tr. Shahan, Freiburg, 1908). On the other hand, Fessler describes patristica as that theological science by which all that concerns faith, morals, or discipline in the writings of the Fathers is collected and sorted. The lives and works of the Fathers are also described by a non-specialized science: literary history. These distinctions are not much observed, nor do they seem very necessary; they are nothing else than aspects of patristic study as it forms part of fundamental theology, of positive theology, and of literary history.
The church fathers are generally divided into the Ante-Nicene Fathers, those who lived and wrote before the Council of Nicaea (325) and the Nicene and Post-Nicene Fathers, those who lived and wrote after 325. In addition, the division of the fathers into Greek and Latin writers is also common. Two of the most prominent Greek Fathers are Justin Martyr and Cyril of Alexandria. Among the Latin Fathers are Tertullian and Augustine of Hippo.
Most patristic texts are available in Jacques Paul Migne's two great patrologies, Patrologia Latina and Patrologia Graeca. For Syriac and other Eastern languages the Patrologia Orientalis is less complete and can be largely supplemented by the Corpus Scriptorum Christianorum Orientalium. Noted collections containing re-edited patristic texts (also discoveries and new attributions) are the Corpus Christianorum, Sources Chrétiennes, Corpus Scriptorum Ecclesiasticorum Latinorum, and on a lesser scale Oxford Early Christian Texts and Fontes Christiani (also Etudes Augustiniennes).