The book was written after. The question is historical events and figures. St. Paul, for example, is a notable historical figure and author. He at first prosecuted early Christians, then converted to Christianity himself, and he was in an intense direct contact with the first disciples of Jesus and other people who firsthand saw Him resurrected.
But that's according to one book. There are many other books that have different claims.
That's according to the direct eyewitness testimony of people some of which later died for it?
So, the book vouches for itself by claiming people totally witnessed it all, and some died?
Even if people died for it, that doesn't prove that it's true. It's circular reasoning.
The book was written after. The question is historical events and figures. St. Paul, for example, is a notable historical figure and author. He at first prosecuted early Christians, then converted to Christianity himself, and he was in an intense direct contact with the first disciples of Jesus and other people who firsthand saw Him resurrected.