Greetings again Towerwatchman,
I could add some statements that show the gradual development of the Trinity by various Early Church Fathers.
I have not extensively read the ECFs and their teaching. The following is taken from the Lecture Slides of one of my Brethren, and he has extensively read and studied some of their writings:
Clement of Rome (1st Century)
The Father alone is God; Jesus is the Son of God, born a mortal man, raised to immortality; the Holy Spirit is God’s power.
Ignatius of Antioch (1st Century)
The Father alone is God; Jesus is the Son of God, born a mortal man, raised to immortality ; the Holy Spirit is God’s power.
Polycarp of Smyrna (1st-2nd Century)
The Father alone is God; Jesus is the Son of God, born a mortal man, raised to immortality; the Holy Spirit is God’s power.
Papias of Hierapolis (1st-2nd Century)
The Father alone is God; Jesus is the Son of God, born a mortal man, raised to immortality; the Holy Spirit is God’s power.
Justin Martyr (2nd Century)
The Father alone is ‘true God’; Jesus is a pre-existent divine being created by God; the Holy Spirit is a type of angel
Irenaeus of Lyons (2nd Century)
The Father alone is ‘true God’; the Son and Holy Spirit are the divine ‘hands of God’, but not fully God in their own right
Tertullian (2nd-3rd Centuries)
Father, Son and Holy Spirit all share the same essence and co-exist equally as God, yet the Son was somehow ‘begotten’ by the Father and there was a time when he did not exist
Origen (2nd-3rd Centuries)
The Father alone is ‘very God’; the Son has always existed, being eternally ‘generated’ by Him; the Holy Spirit’s divinity is derived from the Son
Clement of Alexandria (2nd-3rd Centuries)
The Father alone is God; Jesus and the Holy Spirit are pre-existent divine beings created by Him
Arius (3rd-4th Centuries)
Jesus is the first of God’s creation; a pre-existent divine being
Athanasius (3rd-4th Centuries)
Father, Son and Holy Spirit are equally God; Jesus was and still is, fully God and fully man
1st Council of Constantinople (AD 381)
Re-condemned Arianism, declared that Jesus is fully human yet simultaneously divine; also affirmed that the Holy Spirit is God.
Council of Chalcedon (AD 451)
Declared that Jesus has two natures (human and divine) but is only one person, without sin; also affirmed that Mary is the Mother of God.
I also read the following book and took a few portions from his book that were interesting:
History of the Dogma of the Deity of Christ by A Reville 1904 (from translation 1905) Professor of the History of Religion at the College of France.
Page 4: The maxim of Vincent de Leyrins, more boastful than true, ‘the Church, when it employs new terms, never says anything new’, influenced the entire history of Christianity; philosophers and submissive believers were equally satisfied with it.
After a brief summary of the doctrine of the Trinity he says:
Page 9: Such is the doctrine which, having been slowly elaborated, arrived at supremacy in the Christian Church towards the end of the fifth century, and which, after continuing undisputed, excepting in connection with some obscure heresies, for eleven centuries, has been gradually from the sixteenth century losing its prestige, although it is still the professed belief of the majority of Christians.
Page 10: … the religious sentiment … is not in the least alarmed at contradictions; on the contrary, there are times when it might be said that it seeks and delights in them. They seem to strengthen the impression of mystery, an attitude which belongs to every object of adoration.
Speaking of the developments in the second century:
Page 54: … the ‘celestial being’ increasingly supplanted the human being, except among the Jewish-Christians of the primitive type … These firmly maintained the opinion that Jesus was a man, … fully inspired by God … admitted his miraculous conception.
Page 59: The Platonists began to furnish brilliant recruits to the churches of Asia and Greece, and introduced among them their love of system and their idealism. To state the facts in a few words, Hellenism insensibly supplanted Judaism as the form of Christian thought, and to this is mainly owing the orthodox dogma of the deity of Jesus Christ.
Page 60: Hence the rapidity with which a philosophical doctrine of much earlier origin than Christianity, and at first foreign to the Church, was brought into it, and adapted itself so completely to the prevailing Christology as to become identical therewith, and to pass for the belief which had been professed by the disciples from the beginning.
Page 96: There were some Jewish-Christians who admitted without difficulty the miraculous birth of Jesus, but would not hear of his pre-existence.
Page 105: It is curious to read the incredible subtleties by which Athanasius and the orthodox theologians strove to remove the stumbling-block from the history of a dogma which they desired to represent as having been invariable and complete since the earliest days.
Page 108-109: … the minds of men … either inclined to lay great stress upon the subordination of the Son, in order to keep as close as possible to the facts of Gospel history, or they dwelt strongly upon his divinity, in order to satisfy an ardent piety, which felt as if it could not exalt Christ too highly. From this sprang two doctrines, that of Arius and of Athanasius. In reality, though under other forms, it was a renewal of the struggle between rationalism and mysticism.
Page 115: In reality, Arius, whose character and doctrine have been unjustly vilified by orthodox historians, was stating the ecclesiastical doctrine that had been in common acceptance.
Speaking of the Nicene Creed:
Page 121: … the majority of the council would have preferred a middle course, maintaining the traditional idea of the subordination of the Son to the Father, while ascribing to the Son as much divine attributes as they could without openly passing this limit.
Page 124: Arianism, which had been overcome by the imperial will more than by the free judgement of the bishops, retained its power in the churches.
Page 126: People did not believe at that period in the infallibility of councils. The West alone remained firm in adhesion to the faith of Nicea.
Page 136: The Arian party, representing as it did the opposition to ecclesiastical authority and dogmatising mysticism, was the party generally preferred by the freer minds. It was consequently the least united. For the same reason was it the most opposed to the ascetic, monkish, and superstitious customs which more and more pervaded the church.
Now you may contest some of the fine detail in the two excerpts, but I feel confident that both indicate a reasonable view of the development of the Trinity.
Kind regards
Trevor