This is such an exciting project. And the phrase "the Middle Ages and the Humanism Period" is a bit misleading, because what we may find are transcriptions of ancient texts long considered lost.

One of the most flatly incredible manuscript discoveries of the nineteenth century is a short treatise called the "Didache." We knew that such a thing existed, because writers as early as the 3rd century mention it, but it was presumed lost. An 11th century manuscript of it was found in a library in 1875, and most scholars now believe that the text dates to the first century, making it the oldest known Christian "catechism" (one which, intriguingly, seems to stand outside the Pauline tradition).

Obviously, this was and is an absolutely amazing thing for students of late antiquity in general and early Christianity in particular, and it had been sitting there in plain sight (so to speak) for centuries. It would surprise me not at all if we find similar things in the Vatican collection.