In case anyone actually wants to know the truth... gey a copy of Jurgens, FAITH OF THE EARLY FATHERS, vol. 1, look on page 410, in the scriptural index, and you'll see that there are at least five references to Matthe 28:19 from before Constantine's birth. I don't know how Constantine could have put it in the bible if it was already there before he was born. Besides, as every Church historian knows, Constantine was a supported of the Arian party and not the orthodox Catholics!
I always wanted those books. Maybe I'll get them for myself as a reward when I get the garage cleaned.
You are right....the term Trinity was first coined by Quintus Septimius Florens Tertullianus (ca. 155-230)known as "The Father of the Western Church". He was one of the first great writters of Latin in the early Christian Church.