History is just a matter of believe, mirroing your own ideals and today its also part of a scientific market. People need and want to make money and to justify the position of history as a scientific discipline.
It is of cause really hard to see this as persons who are in this circle.
Just one simple fact:
Most people cant even remember, what they ate 2 days ago and every information we store into our brains is altered from reality. Even worse is what happens to a message after communicating it to other people. Even more worse is translating between to languages, which is why most movies get worse after translating and to read ancient textes without any native speakers, who know the feeling and true meaning of words and the way of thinking. Even in written documents in a still spoken tongue (Even in english) people debate over things that were written, because there isnt anything like 100%truth in written or spoken words. So, if there is one document we read about lets say the roman army in latin, the possbility of someone really knowing the thruth afterwards are less than winning in the lottery.
Still, some people claim to know with a high possibility what happend in EB Timeframe? The fact that there are people who claim roman superiority and people who qualify that statemen or openly disagree is further proove that it is a matter of believing.

People, who studied 100years ago thought they knew something for sure. 100years of scientific and philosophical improvements later we know that this is not true.
It is funny, how the archaelogy in anglosaxon countries is so modern in its methods, but still there are so archaelogists, who dont believe or recall that they are only humans and have only evidence. They arent looking for the truth, they are looking for probabilities.