One would think there should be no controversy over the idea of the trinity seeing that many ancient cultures had trinity gods before the New Testament days happened.
One of the most common beliefs among Pagan cultures was in a trinity of gods. We find this among the Egyptians, Indians (of India), Japanese, Sumarians, Chaldeans, and of course, the Babylonians, to where historians trace the roots of trinitarism.
It's been an obvious idealism for 5,000 years.
The Trinity, implied by the word itself, is three Persons in ONE God. How many of those triple gods were three AND one? The reason I ask is that the one God of the Bible is three Persons, a Mystery that cannot be discovered through logic and reasoning. Therefore, that Tri-une God of the Gospel of John had to have revealed himself to the biblical writer, because no one could have dreamed or thought him up.