There is a school of thought which says that ancient Greek and Roman historians were more interested in telling pretty stories than about critically comparing different reports to understand what had happened in the past. Generally advocates of this view appeal to later and Roman writers like Livy and Tacitus, and to proscriptions by rhetoricians about how history ought to be written; opponents appeal to earlier and Greeker writers like Thucydides, and note that those proscriptions were seldom written by working historians, and often fail to say what the relativists wish they said. And like unto the battle-lines in Homer, back and forth the combat goes, enlivening the discussion periods at conferences, fattening journals, and keeping librarians busy delivering the latest salvo. Since ancient historians only left incidental traces of their working methods in their writings, and not many non-historians wrote anything about the subject at all, the debate will keep scholars happily bickering for decades to come. I tend to lean against this way of thinking, but because the debate focuses on later periods than I do, I would recommend that interested readers check Luke Pitcher’s book below for an introduction.
One of my favorite tools in such situations is to look for parallels. Medievalists tell me that very little is known about how chroniclers worked in the middle ages, and little research has been done (Anne Curry’s book on Agincourt has some helpful footnotes here). More seems to be known about writers from the sixteenth century as in the following quote from Robert Black, Machiavelli (Routledge: London and New York, 2013) pp. 248-252. I was struck by his remarks on how Italian humanists in the fifteenth and sixteenth centuries wrote history, and since they are evidence against my own views they deserve to be quoted:
Machiavelli intended his work to conform to the norms of humanist history, aiming to imitate Bruni’s and Poggio’s Florentine histories. The text is laden with features characteristic of ancient Roman historiography such as lengthy speeches … It is clear that Machiavelli was attempting to recreate the periodic style of the classical Roman historians, and particularly Sallust and Livy, in the modern vernacular … In line with the conventions of humanist historiography, Machiavelli showed little concern for factual accuracy. The work’s many methodological shortcomings, errors and even inventions have been frequently highlighted, beginning in the sixteenth century with the definitive historian of grand-ducal Florence, Scipio Ammirato (1531-1601) …