In other words you have already accounted for them not being true but being fictional.
No, I haven't.
I'm greatly puzzled by your not being able to distinguish between fictional and allegorical.
But *as assertions of fact* they are vastly more ridiculous than anything Gibbon gets wrong.
Really ?Let's see.
The Bible (abridged): God created the world and everything that's in it in seven days.
In order to assess the merits of this proposition, which was not originally written in English, one has to know the original Hebrew meanings of the words therein. I don't. Do you?
Gibbon (in plain English, abridged): Christianity is the main culprit for the decadence of the Roman Empire.
If this is so, how come that those decadent Christians were able to restore, preserve and defend the most populous and civilized areas of their empire --- which, btw, they never called anything else than Roman; Byzantine is a malicious, ideologically motivated confection --- for almost a millenium after the Western areas fell prey to Germanic barbarians?