Yes there is kosta and you know better.
How do we "know" that Paul was in Rome?
How do we know of the caesars? David?, Solomon? Your low standard for historicity is laughable - legitimate historians do not doubt the existence of Jesus
But since I am here, I will answer your question, in proper context.
You write: How do we know of the caesars? David?, Solomon?...Your low standard for historicity is laughable?
My comment to which you are replying was in reference to P-Marlowe's matter-of-fact "the authors of those gospel accounts" who "gave their lives in defense of their testimony."
To which I replied "Do you have extra biblical evidence of that?" And the answer, of course, is no, he doesn't, and neither do you, or anyone else. What we know about the authors of those gospel accounts is legend.
Find one example of alleged martyrdom of the apostles that is not legendary.
Which historical document mentions any of them?
If my historical standards are low, as you say, what do you call standards of unshakable belief based on legends? Ignorance?