Question

Which of these historians was one of the first to emphasize documented facts over unverifiable stories

Answer 1

A lot of historians have had an important role in the history of... historiography. We usually associate the birth of history with the work of Herodotus in the 5th century BC. He devoted his time to document stories about the old days and habits of the various people he visited. Other historians like Thucydides during the Peloponnesian war took a more scientific approach. Instead of documenting tales and anything of interest, he only documented facts that he could verify himself; some other parts he specifically mentioned that he could not verify them. In a sense he can be called the father of the science of history since until then verification of historical work was not being emphasized. Other historians, like Xenophon  and Tacitus followed in his footsteps.

Answer 2

The answer is actually Tacitus