Observation: The reason for the late date of the period is that they were so busy just standing for the faith under persecution that they didn’t have time for theological discussions of differences.
The beginning of Creedal development:
Began with the Emperor Constantine calling councils for the purpose of seeking to unify the Empire. Unify under one religion and you have the problem solved. Creeds which resulted became the rule of orthodox teaching and still remain today.
Theological Council held (in the east) as called by the Emperor:
Relationship of the Son to the Father, Arias responsible.
Opposing views:
Arias: claimed Christ had not existed from all eternity, but was created in past eternity and not of the same substance as the Father. Christ was not co-equal, co-eternal, and co-substantial with the Father Christ was divine but not deity.
Athanasius: Christ was eternal, of same substance but a different person. Christ was co-equal, co-eternal, Co-substantial with the Father in a trinity relationship.
Eusebius: Christ was begotten and of like substance. This was a compromise position.
Decision of the Council of Nicea on the doctrine, 325 AD. Accepted the creed of Eusebius generally, but not the part on the relationship of the Son to the Father as stated above. Accepted Athanasius’ position on the relationship of the Son to the Father.
Nicene Creed enlarged as it exists today at the Council of Constantinople in 381 AD.
Decision of the Council of Constantinople of 381 AD: Holy Spirit: co-equal, co-eternal and co-substantial. Asserted the humanity of Christ.
Christological doctrines and councils held:
The Monophysite controversy: the relationship of the two natures of Christ.
Opposing views:
Apollinaris: Christ had a true body and soul but the spirit of man was replaced in Christ by the Logos.
Nestorius: Christ was man, had two natures, but in a mechanical union rather than in an organic form. Emphasized Mary as the mother of the human Christ. Christ was perfect man, morally linked with deity, but minimized the deity of Christ.
Eutychus: two natures of Christ fused into one, the divine nature. Councils deciding on the Monophysite controversy: Council of Chalcedon: 451 AD. Christ complete in Godhead and complete in manhood. Truly God and truly man.
The Monothelite Controversy: the relationship of the two wills of Christ.
The Monothelite position: Christ had only one will, not two.
The Council of Constantinople decision regarding the wills of Christ. Christ had two wills, a human and divine will. They were united into one unity with the human will subject to the divine will.
Anthropological doctrines relating to the matter of salvation (in the West)
Pelagius view of salvation: He denied total depravity. He taught that the human will is free to cooperate with God in the attainment of holiness and can make use of such aids as the Bible, reason, and example of Christ.
Augustine: Believed in total depravity. Man’s will is entirely corrupted, all inherit sin in Adam and cannot escape original sin. Salvation can be only to the elect through the grace of God. He was strong on the irresistible grace of God.
John Cassianius: All men are sinful because of the fall of Adam. Their wills are weakened but not totally depraved. Teared the irresistible grace of God, man’s partially free will can cooperate in divine grace in the process of salvation.
Following the councils, or at least the Nicene Council, we find the period of the Post Nicene Fathers. The purpose of these men was to study the Scriptures along scientific lines in order to develop their theological meaning. Not apologetical because persecution was basically past for the time being, not polemical because the councils had solved the heresies.