Also we do know there were many competing narratives describing the life of Christ just a few hundred years after he died. After the Church become more established scholars spent a lot of time and effort trying to determine which ones were "accurate" or not and suppressing the other narratives. It's not like anyone can verify it they got it right or not, though.
Usually the arguments are not about whether a major historical figure like Christ or Mohamed etc. existed but the exact context and accounts of their lives, beliefs and actions. Also both of these men live in literate societies yet just a few hundred years after the deaths the facts already were very blurry and uncertain. Hypothetical Moses on the other hand lived in an illiterate society and history wasn't written down for 500+ (if not quite a bit more) years, even if there is a grain of truth in them (i.e. some sort of migration or interaction between Canaan and Egypt - which is not at all far fetched) the actual details might have become 99% fictional after being passed down orally through dozens of generations.
Yeah, and in the process of converting to Christianity, Romans began rewriting their history and erasing their past. Which is exactly what we are talking about right now. You claimed "The idea that some random historian or politician simply convinced everyone his fiction story was true and central to their identity - and it worked time after time AND everyone else bought into it - is clearly absurd." And I'm giving you clear historic examples where exactly that happened. But now you want to make it about whether or not the people that did that existed or not.
> Or are you saying there was never any man named Jesus who was crucified?
Likely a man named Jesus existed because we have non-biblical documents from the time period (Josephus and the Sanhedrin) recording that he existed. Further, there are parts of the biblical narrative that are indicative that he was a real person. The census story in Luke, for example, is a convoluted story that you'd only tell if there was a real problem with Jesus, that he was well known to be from Nazareth and not Bethlehem. Were Jesus a complete myth there's no reason the gospel author wouldn't just say "And he was born in Bethlehem as prophesied"
> I guess you may as well argue that - both him and Paul could have been invented.
Again, nope, because we actually have a fair bit of contemporary documents about the existence of both. Something we don't have for Romulus.
> used incorporated what he knew of what he believed to be true history.
Right, I'm not arguing about Mohamed existing, I'm arguing that he made up history which people believed. Or more precisely, his followers did. Mohammad was illiterate and the Quran was written some 50 years after he died.
> I think Joseph Smith is rather too well attested to claim he did not exist.
Joseph claimed to be a historian who documented the events of the ancient americas. He claimed to have found records of those events and "transcribed" a book.
Quite similar to Romulus. And as it turns out, yeah, an entire religion of people believe him that Mormon and Moroni, Nephi and Lehi are all real people that really existed.
I mean, almost uncannily, the events he wrote about were 1000 years in the past from him.
I'm not sure that's true. Of course some some details might have been purposefully (or not) ignored or twisted. While obviously Christian scholars were quite picky on which pagan texts to preserve or not (due to various reasons) there is not a lot reason to believe that generally they did their best to copy them faithfully. Of course we are talking about a highly literate society with a strong tradition of analytical history (which was very unique by pre-medieval standards at least).
> Quite similar to Romulus
The claim that some specific historian might have invented him out of thin air is far fetched and not really substantiated. Much more likely that the legend evolved over many generations and became a mishmash of fact and fiction over hundreds of years before someone actually wrote it down. Based on other similar cases it's highly likely that there were many competing traditions by Livy's time. So yes, he did very likely tried to reconcile them and picked how to synthesize the narrative but it's hard to imagine he could have actually invented it because there were plenty of people and other historians who could have called him out on it.