Two recurring themes in fundamental Baptist thought are the idea of Landmarkism/Trail of Blood and the idea that the church ought to prefer the KJV above other translations, or even to ban the use of other translations altogether. Interestingly, they are linked by a most unlikely (at least to those in these movements) document; Jerome's Vulgate, the Bible in Latin.
First,
here's a primer on the
"Trail of Blood" from a source that fully endorses it. If you read it carefully, you'll find that the claim that there were "always Baptists" really rests, as far as I can tell, on three (likely suspect) quotes of Newton, Mosheim, and Hosius on page 4--and none of them are primary sources, all of them being born after the Fall of Constantinople. Were I a lawyer, I'd not like to rest my case on this evidence!
More or less, it appears that the "
Trail of Blood" is simply a way of trying to establish that Baptist theology is ancient--under the idea that if it's old, it's right, just like the theories of luminiferous aether, caloric, and Aristotelian physics are better than the work of Einstein, Rumford, and Newton because they are older, too.
(yet another reason why you should learn logic and teach it to your children)
Let us now consider the Vulgate. The significance of this is that Europe was largely illiterate in the Dark and Middle Ages, and the only Bible the few literate people had would have been the Vulgate. Love it or hate it, it is what they had, and here's how they translated the Greek word "baptizo."
"Baptizo" with Latin conjugations. In other words, a Greek word with a primary meaning of "immerse" (and numerous related meanings) was replaced--as in the KJV--with a transliterated word referring only to the ordinance of baptism.
Now consider; how are you going to figure out that the Bible tells you to immerse if it doesn't use that word, and you neither know Greek nor have access to Greek manuscripts? It is possible one might infer it from the Baptism of John, but doubtful--our paedobaptist friends have numerous explanations for that passage.
So we see that unless somehow the knowledge of Greek penetrated these churches, it is extremely doubtful that they would have become Baptists. Interestingly, most Landmark Baptists will insist on the KJV, which of course....
...makes the same translation choice, or "error" if you will, as the Vulgate.
I treasure authentic fundamentalism, and I treasure authentic Baptist distinctives. However, holding to theories in the face of a lack of evidence and a Bible translation most Protestants abhorred until the 18th century (it had the apocrypha until then) seems like an odd way to hold to what truly distinguishes Baptists.