"God is not a God of confusion"
The Forgotten God
If indeed God is a trinity of three persons in one, his people seem to have forgotten about Him. We can quickly see from early christian writings that no one in the early decades of the church had a Trinitarian concept of God. In the earliest times (70-130 A.D.), we find Christians simply referring to the Father as the one God Almighty. A little latter, during the age of the Greek apologists, (130-180), Christians were called upon to provide an apologetic of the Christian faith, but we do not find anyone explaining God as if the Supreme Being was a divine unified triad of three persons. Aristides, Justin Martyr, Athengoras, Theophilus, and Irenaeus all point to God the Father as the one God. Martyr even identifies the Father as the one true God and Jesus as His Son and an angel and "another god." They tend to explain the relationship of God, and His Spirit, and His Son in terms of the sun analogy, where the Father is the sun and the Son is the light emanating out of the sun. Yet, they would not say all three are the sun proper and true. Or they may explain this relationship in terms of human speech. God had a word in his heart, his Logos, and he begat this Word on the breath of His mouth, that is, His Spirit, and creation comes to be. In whatever way it is explained, God is always clearly distinguished from his Logos Son and His Spirit. At times, it even appears they say the Logos Son is the Spirit. Of course they recognize there are three. But then everyone does. Yet none identified these three as the one God.
The non-Trinitarian mindset becomes even more pronounced when the Monarchians arrive on the scene. The Monarchian modalists claim God is one person manfesting himself as three different beings, usually sucessively. The response of the church here is very telling. Instead of roundly defending a Trinitarian mindset and refuting the monarchians from that basis, the church at large did one of two things. Some of them entertained whether the modalist was a good model to explain God. Others who could see that it was not a good model did not object on the grounds of Trinitarian concepts. In other words, they did not believe modalism to be true, but they most certainly did not offer a Trinitarian argument to counter the modalist teaching. Modalism was the catalyst of Trinitarianism. Someone had to come up with an answer.
It would not be until the latter half of the third century that Trinitarian concepts started to emerge. In the early half of the third century, Tertullian offered an explanation of God and his relationship to the Son and the Spirit in terminology used today by Trinitarians. However, although his terminology was the same, his concepts were not. Tertuallian believed the Father was the one true God, and that he was alone before creation and there was a time when the Son was not. Pressured by the Sabellians, the opponents of the modalists had to come up with a sound explanation. Around the middle of the third century, we can see that the leaders of the church were starting to envision God as a Trinity of three persons, similar to today's Trinitarian dogma. At this time however, it was still vaguely defined. And this fact is seen at the beginning of the fourth century when Arius had opportunity to challege his theological rivals.
It is clear that Trinitarian doctrine was not an apostolic tradition. If it were handed down by the apostles, this would have been the simple response to the dynamic monarchians, the modalists, and whoever else came along.