Your position is nonsense. The idea that any world was shaken because of the gospel of Barnabas is simply ridiculous.

You yourself point out why historians have dated it very late, and find it of little relevance to historical studies. That supposed prophetic reference to Islam?

That's just one reason historians know that Barnabas was written in the 14th or 15th century CE. It has no relevance to Christianity or Islam, because it's a forgery.

No reputable scholar anywhere believes otherwise, and they have excellent factual foundation for knowing what they know.

Again, you are assertion that the Gospel of Barnabas shook Christianity or historians is simply nonsense. The shaking you describe did not happen.