The KJV is based on the Masoretic text. Which dates about 700 years after Nicaea.
The RCC on the other hand, uses Codex Vaticanus as the primary source text.
Dated... when?
And, since most of the earliest fathers' writings match those texts in 700 AD, it's pretty clear that those extant texts are copies of copies of scripture that was available to the earliest church fathers...
The RCC on the other hand, uses Codex Vaticanus as the primary source text.
Which the earliest church fathers didn't use...