The invention of the comparative history method

[timelets]

...let us consider the proper qualities and functions of history. A historian should not use his narrative to astound† his readers with sensationalism, nor should he make up plausible speeches and list all the possible consequences of events. A historian should leave these things to tragic poets, and should focus exclusively on what was actually done and said, even if some of these facts are rather unexciting. History and tragedy do not serve the same purposes. On the contrary, it is the job of a tragic poet to astound and entertain his audience for a moment by means of the most convincing words he can find, but it is the job of a historian to instruct and persuade his readers for all time by means of deeds that actually took place and words that were actually spoken. The object in the first case is to create a plausible fiction in order to beguile an audience, in the second case to write what is true in order to educate the reader.
...
...Phylarchus’ penchant for melodrama led him to write not just a pack of lies, but a pack of implausible lies. His ineptitude is so outrageous that he failed even to note an obvious par- allel: that at much the same time the Achaeans also captured Tegea, and treated the inhabitants quite differently. And yet if Achaean ‘cruelty’ were the determining factor, the Tegeans too would presumably have suffered the same fate as those who fell into Achaean hands at the same time. If the Mantineans were singled out for special treatment, there plainly must have been a special reason for anger in their case.


--- Polybius, The Histories.