Eusebius (ca. 265 – ca.339) could be written of in either the third or fourth centuries. A brief treatment of his contributions will be treated in this section as it is also the section that discusses the Nicene Council at which he played a prominent role. Eusebius is considered to be the father of church history. Like Origen, Eusebius was a prolific writer with four key works that should be mentioned here.
First was the work Ecclesiastical History written in ten volumes beginning around 303 and being revised several times between Emperor Constantine’s Edict of Toleration and his victory over Eastern Emperor Licinius. After being elected bishop of Caesarea, Eusebius wrote his three largest works. Preparation is a fifteen volume work refuting paganism; Demonstration of the Gospel is a twenty volume work that examines the fulfillment Old Testament prophesies in Christ; Chronicle is a world history to 303 and likely a prelude to the earlier historical work.
When confronted with a charge of heresy for his Arian leanings in 325 which resulted in his provisional excommunication, Eusebius successfully argued his defense at the Council of Nicea later in 325 before Emperor Constantine. His of a creed of Caesarea, though successful, would be altered to become the Nicene Creed and included the key homoousios phrase that Eusebius was never completely supportive of. Eusebius was the president of the Council of Tyre and served on two other councils before his death in 339.
The Council of Nicea was the first ecumenical council in the history of the church and was convened by Emperor Constantine himself to address the schism in the church that formed over Arianism. Among other things addressed at Nicea was an agreement on when to celebrate Easter and a ruling on the Melitian Schism in Egypt. For all of the issues addressed at Nicea, it is most notable what is not addressed: the New Testament canon. The importance of the issues of the day left the issue of canonization for another council later in the fourth century.
In 367, Bishop Athanasius of Alexandria in his Festival Letter for the coming Easter holiday gave a full and final declaration of which books were to be read and included an admonition that nothing should be added to nor taken away from this list. It was not until the third Council of Carthage in 397 that the issue of the New Testament canon would be formally addressed. It was this council that decreed that nothing should be read in the church under the name of divine Scriptures except the canonical writings which included the twenty-seven books we know today as the New Testament. Further, the council could only list the books that received a general consensus of use as properly a canon.