[pqtyw]

> The idea that some random historian or politician simply convinced everyone his fiction story

Not on purpose, it's just that without written history it's very easy for stories to drift very far from the historical facts. There might haven been a Roman king Romulus who did something important (then again he might have been created over time by merging several figures - i.e. it's more likely that he was named after the city and not the other way around).

We actually have real documented historical cases of this process occurring, the whole genre of Germanic heroic legends. They include various historical figures like Theodoric, Attila the Hun and others but the actual facts were mostly corrupted beyond recognition. Also this process took 500-800 years and developed in environment in which existing historical written sources on the same events did exist (even if they weren't directly accessible to most).