Hi
@TheLightWithin – welcome aboard!
@RJM has listed a number of threads, and I think I can say I'm a vociferous Trinitarian apologist here. So I won't rake over the bones of a well-discussed debate, but I would like to put in a couple of theological nuances ...
... but I definitely see the relevance of Constantine and the Arian priest (Arianism by the way is totally different from Aryanism but I think others have defined that already) Constantine and Arius, for whom Arian doctrine was named, as a HUGE part of early Christian history and early Church history.
Indeed, but largely in retrospect. At the time it was seen as a 'local' problem for the bishop of Alexandria to sort out.
The Western Church was not particularly engaged in the dispute, and nor did it play any significant part in its resolution. In the end, the Arian Question was a dispute in the Eastern Church, and was resolved by Eastern theologians, rather than by imperial coercion or papal ruling.
Of course, Constantine getting involved complicated issues, but we should not lose sight of the fact that on the ground, at the time, it was not seen to be as important as it subsequently became. Few Western bishops attended Nicaea, the Pope sent a couple of representatives, which says something about the relationship between pope and emperor ...
Had the councils ruled differently, in favor of Arius, for example, the Church would have taught non-Trinitarian doctrines.
I'm afraid that's not quite right – had the church ruled in favour of Arius, we would have had a distinctly hierarchical Trinity, but the Three Persons, Father Son and Holy Spirit, we well-established by then. He was not so much demoting Jesus as defining his nature/substance as different to the nature/substance of the Father, but nevertheless divine.
As much as Arianism seems influential, as a doctrine it ended with him. Later semi-Arians moved closer to what would eventually emerge as the orthodox position, but could never agree amongst themselves.
Please read the book When Jesus Became God: The Struggle to Define Christianity during the Last Days of Rome / Richard E Rubenstein. Plus the historical narrative is just so interesting.
Oh indeed! LOL, I could bang on about it for hours (be warned!), the nuances of theology are of great interest to me ... but please don't let your views rest on one opinion! I've looked at interest at reviews of the book, and I'm not sold, sadly to say ... but I do applaud any attempt to bring the issue to life, as it were.