I do a lot of games on ancient and medieval topics. We often know far less about those battles and conflicts than we do about modern ones. Primary sources are fewer in number and also less reliable; the line between history and propaganda, always thin, becomes especially and uncomfortably porous the further back we go. When we do have multiple sources to draw from, they're often contradictory. It's common to be unsure where and when a battle took place, but there are also battles where we don't know who was on which side, who won, or if the battle even took place at all.
A good example is the Battle of Corbridge, which was one of the eight in my game The Great Heathen Army. As I mentioned in that game's background material, "Aethelflaed led an army against Viking invaders at the Second Battle of Corbridge. The problem is that there probably wasn't a Second Battle of Corbridge. Unless there were three." It's enough to make one pine for the certainty that comes with knowing that at the Battle of the Bulge began at 5:30 am on 16 December 1944.
Except it's not, though, because for all the problems that come with using medieval and ancient sources, there are two big pluses in their favor. The first is that my job as the designer in these cases isn't to replicate history faithfully and exactly, because that is straight-up impossible, but to do so plausibly. If I'm doing a Bulge game, and I have a single brigade or regiment or division in the wrong hex or with the wrong strength point value or missing entirely, I am going to get lambasted all the way from here to Bastogne!
But no one has a detailed order of battle for the Battle of Wednesfield or what-have-you. Chances are in fact that any numbers provided in the sources are dead wrong and vastly inflated. There's no pressure to get everything exactly right, but only to create a plausible (and playable) version of the events. Rather than leaning on the crutch of replicating set-in-stone numbers and proven facts, the designer must rely on their own judgment. The model, then, is only as sound as that judgment, and so it certainly has its own challenges and pitfalls.
Section of the initial page of the Peterborough Chronicle, one of the Anglo-Saxon Chronicles.
But on the whole I find those challenges less tedious than hunting down where this regiment was at a given time or how they performed on a particular day. There's a danger that new designers are especially prone to, where they try to cram in all their research into the design, where the level of detail is inappropriate for the scale of the game. It's hard to do that when all you have to go on is a couple of paragraphs in the Annals of Fulda or the Anglo-Saxon Chronicle. In fact, the description of the battle is more likely to have only one detail that really stands out.
But then you can build the whole thing around that one detail, make that the thrust of your story, make that the scenario special rule that elevates the thing: "this is the one with the traitor", "this is the one with the ambush". I remember hearing Mark Herman talk on Guns Dice Butter about how Jim Dunnigan would focus on a single element or aspect of a battle or conflict, and it's something I often try to do with my own work. And I can tell you, it's a whole heck of a lot simpler to focus on just one thing when the sources only give you one thing to begin with.
So in many ways, ancient and medieval sources make my job - well, not easier, exactly, but they play to my strengths and predilections. That's the first big plus I mentioned above. The second is, ancient and medieval primary sources are more fun.
Now, they're not always fun. The Anglo-Saxon Chronicle is a slog if ever there was one, and the Annals of the Four Masters isn't much better. But even those dry-as-dust matter-of-fact texts sometimes have really delightfully bonkers stuff in them that make the slog worth it. I'm reading about this king or that one, this bishop and his beef with this other bishop, and all of the sudden there's a random story about murder and cannibalism that has nothing to do with anything else, and is only in the book because it happened that year and the monk who was writing the chronicle decided to jot it down.
Detail of "Battle of Clontarf", oil on canvas, Hugh Frazer, 1826
Some sources are more delightful than others. The Irish text Cogad Gáedel re Gallaib is one of my absolute all-time favorite primary sources, mostly because of this sentence describing the Battle of Clontarf:
Then the fearful, murderous, hard-hearted, terrific, vehement, impetuous battalion of the Denmarkians, and the vehement, irresistible, unanswerable phalanx; and the fine, intelligent, acute, fierce, valorous, mighty, royal, gifted, renowned champions of the Del Cais, and all the descendants of Oilioll Olum met in one place; and there was fought between them a battle, furious, bloody, repulsive, crimson, gory, boisterous, manly, rough, fierce, unmerciful, hostile, on both sides; and they began to hew and cleave, and stab, and cut to slaughter, to mutilate each other; and they maimed, and they cut, comely, graceful, mailed bodies of noble, pleasant, courteous, affable, accomplished men on both sides there.
That same battle, we are solemnly informed, also saw Murchad mac Brian kill a hundred men: "there fell fifty by his right hand, and fifty by his left... and he never repeated a blow to any one, but only the one blow, and neither shield nor mail-coat was proof to resist any of those blows, or prevent its cutting the body, the skull, or the bone of every one of them."
I'm pretty sure that's not even remotely true, nor do I think there were witches and demons present on the battlefield, though the Cogadh seems pretty sure that there were, and when I do the Clontarf scenario for a future Shields & Swords II game, I'm pretty sure I'm not going to do a special dual-wielding rule for good ol' Murchad. So none of it makes it easier to design a game on the battle, but it doesn't have to. It remains an absolute joy to read, and sometimes that's all you need.
The game currently on my table is With It Or On It, covering battles in the Greco-Persian and Peloponnesian Wars, and so as you'd expect, I've got Herodotus and Thucydides on tap. Since I'm doing a battle game, and since I have a fairly decent grounding in the tactics and armaments of the day, I only really need to read what they have to say about those specific battles, and none of those descriptions run more than two or three pages. I got all the actionable intel I needed in the space of an afternoon.
But I'm still reading Herodotus, not for any practical reason, but because the book - particularly in Tom Holland's lively and richly annotated 2013 translation - is such a joy and a revelation to read. Here is a guy that loves to tell a story. In fact, he loves to tell a story so much that in the middle of a story he will stop and tell you a completely different and unrelated story for twenty or thirty pages before coming back to the first one! He loves to tell a story so much that he will tell you two or three versions of the same story and leave it up to you to decide which, if any of them, are true! It's gossipy, exciting, sexy, gory - on that last point, I actually had to stop reading for a while when he was discussing the Scythians, as it's really over-the-top with lots of impalements and dismemberment and I'm frankly a little squeamish.The point being, however, is that when I read Herodotus and other primary sources from way back when, it doesn't feel like work or "research", but like I'm reading them for pleasure and my own entertainment. It's yet another reason why my job is the best job in the world.