Ante-Nicene Period

The Ante-Nicene Period (literally meaning "before Nicaea") of the history of early Christianity was the period following the Apostolic Age of the 1st century down to the First Council of Nicaea in 325. This period of Christian history had a significant impact on the unity of doctrine across all Christendom and the spreading of Christianity to a greater area of the world. Those seen as prominent figures of this era, referred to as the Ante-Nicene Fathers or Proto-orthodox Christians, generally agreed on most doctrine while the teachings of those early Christian writers which the general majority considered to be heretical, were rejected.

Christianity throughout the 2nd and 3rd centuries generally has been less studied than that of the periods that came before (Apostolic Age) and after it (First seven Ecumenical Councils). This is reflected in that it is usually referred to in terms of the adjacent periods with names as such "post-apostolic" (after the period of 1st century formative Christianity) and "ante-Nicene" (before the First Council of Nicaea). The 2nd and 3rd centuries were, however, quite important in the development of Christianity.

There is a relative lack of material for this period compared with the later Church Father period. For example, Ante-Nicene Fathers, a widely used collection that contains most 2nd and 3rd century writings, fills nine volumes, and includes the writings of the Apostolic Fathers, Apologists, Clement of Alexandria, Irenaeus of Lyons, Origen of Alexandria and the New Testament Apocrypha, among others. In contrast, Nicene and Post-Nicene Fathers (consisting mainly of Augustine, Jerome and Chrysostom) fills twenty-eight volumes.

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