I'm intrigued by the story of Herostratus, who burned down the Temple of Artemis in an attempt to gain eternal fame. After the deed he was sentenced to death and, importantly, condemned to be forgotten. It was forbidden for anyone to mention his name so that he would not go down in history as he wanted. Obviously, this punishment does not seem to have worked as we now still know his name.
I was wondering if we are sure that his name really was Herostratus and that this is not just a legend?
I'm really not sure how to approach this question, because it seems to rest in some sort of confusion about the way source material works. Our sources say that his name was Herostratus, namely Aelian, Strabo, and Solinus. Valerius Maximus does not refer to him directly by name, but mentions that Theopompus included the arsonist's name in his history in violation of the Ephesians' damnatio (actually Valerius Maximus refers to it as "decreto memoriam abolendo"). Theopompus was a Chian, and even if the Ephesians declared this ban by law it would not have applied to him or anyone else outside Ephesus in any case.
Is it possible that our sources are buffaloing us? Yeah, I guess so, but how the hell would we know? You could say that about just about any event in our texts, with varying degrees of plausibility. The chances that we're being buffaloed here are maybe a little bit better than most instances, but ultimately we have multiple sources attesting to the name of this individual, one of which even gives us the source for his information. Unless it can be shown plausibly that there is some kind of a separate tradition being drawn on here--and no such suggestion is known to me--we either have to trust our sources (no matter how tentatively) or simply rejecting them. Rejecting them generally means providing some alternative though, or some reason for just tossing them all out, and since the name is preserved in several sources it becomes harder to just chuck them all. Also, Valerius Maximus does not really tell us what sort of decree was made, and if it was anything like the damnatio memoriae of later Roman imperial law the ban was not on all erasure of the arsonist's name, but purely the destruction of his public identity. But that's speculation
In the end, my verdict (and I think the verdict of any classicist in his right mind) would be to say that, well, that's what our sources tell us. Is it beyond reasonable doubt that they're not full of shit? Nah, probably not--but how would we know, and what alternative do we have? So we might as well tentatively accept it, or simply not mention his name at all if we're really skeptical