Incunabula

This is Vlad the Impaler - better known as Dracula.

Usually I would never lead a reader to the Wiki as it is chock full of what researchers call "Entertainment Tonight History".  This article, however, took some reading  and checking of footnotes and it seems to have jumped through a lot of the hoops that make for good historical research.

There is a thing called "primary sources" meaning that the trail back in history comes to an end at the event itself and all the rest of it is just stuff written about it.   An event happens but one time. Everything else is just stuff written about the event that is written about the writing about the event.  So you look, as an historian, for the Incunabulum or ""the earliest stages or first traces in the development of anything"...the first account, the first writing about something, the eyewitness or the speech or document read, performed, whatever - the primary source.