It took your religion 400 years to invent a description of the Trinity, apparently because it didn't like what the scriptures had to say about the Trinity...
And anyone who doesn't accept your religion's invention is a heretic...
Ya, you got it...
Please post early Christian writings to support your belief of the Trinity?
I can post many to support Catholic and mainstream protestant beliefs on the Trinity according to my faith.
Something becoming dogma has only to do with heretics effecting the faithful and gaining ground, it has nothing to do with a time frame