The basic idea, I gather, is that when someone writes a history, that piece of writing is itself a part of history. That piece of writing gives us an indication of what people at the time of the writing felt about history and how they fit into it.
What did the historian think was important to record? What did the historian think was unnecessary to record? Which prejudices were praised and which were argued against (or assumed to be wrong)? Was the writing formal or conversational? Was the audience assume to be learned or hoi polloi?
All these things and more make the historian’s work a piece of history in its own account.
I’ve only just started, so we’re on Herodotus. I’ve never read Herodotus, but of course I’ve heard of some of the things he wrote about (Thermopylae, for example). Today’s tidbit has nothing to do with the premise above. It’s just interesting stuff:
Apparently, when the great Persion leader Xerxes tried to have his ships cross the Dardanelles, they were beaten back by storms. Xerxes was pissed off by that, so he had his men whip the water and brand it with hot irons. That’ll teach it.
Bonus tidbit: A servant, who had served extremely well and faithfully, begged to have his oldest son sent home from the fighting. Xerxes had the son cut in half, then had the army pass between the two halves on the way to war.