I’m preparing to launch a new campaign with a totally homebrew setting. What I’m not sure about is how much my players should be aware of at the start of the game. Their characters will all be native to the continent, should they be familiar with all the countries therein? Would they know of those countries’ rulers? The wars that shaped those countries? How much history do I need to have immediately prepared for them to refer to when making their characters and writing backstories, and how much should be uncovered through gameplay? I would be so grateful for any advice you might have! (If it matters, my players run the gamut in experience—one has been in a dozen games, two are complete TTRPG virgins, the rest fall in the middle.)
So, some of this is going to depend on the tone of your game--for example, in a political-intrigue-heavy game, knowing basic politics will make everyone’s lives easier.
My rule of thumb generally is that if a player expresses an interest in knowing some things about history (for instance, their PC has history proficiency, or has goals related to politics/history in some way), you should focus on giving them history that’s closely tied to what that character would reasonably know and be interested in. Most folks don’t know the political history of neighboring countries, unless they are a border region or have some other personal tie to the information like immigration status or a politically influential family, for example.
“How much should be uncovered through gameplay” is another great question that also depends on the game. If you’re interested in having things of historical significance play a role in the game itself, like an old king returning to life or a long-defeated evil rising up again, then I would recommend waiting to reveal most of that information. Put another way, the things PCs discover should have consequences. Information like the name of a neighboring ruler is unlikely to have consequences--but knowing the neighboring king is the bastard half-brother of this nation’s queen with a claim to the throne here may upend the political landscape and have implications for the party if there’s tension between these two nations.
The biggest and most relevant history things you can give your players beforehand are:
1. Names of major cities, rulers, countries, etc. Think of what a tourist would know about a neighboring country--info about the local Wine Country is more interesting to the PCs than the names of bridges and who built them, you know?
2. Cultural artifacts that might be crossing borders. Think music, art, food, language, clothes. If you find yourself stuck for this, look up real cultures similar to the one you’re building and use that as inspiration. Don’t over-infodump this; choose details that will most strongly appeal to a character (like an entertainer knowing different music styles, or a street fighter studying a nearby culture’s martial art tradition).
3. Conflict. I would argue this is the most important one. You don’t need to have every war planned out, of course! Pick and choose a couple significant, current political conflicts that might affect the players. A neighboring nation might be a sugar exporter but recently instituted an embargo in the place the PCs live, causing a sugar shortage. You as the DM should know why there’s an embargo (political leverage, reaction to a different embargo, resisting a military occupation?) but the PCs might not know that--all they know is there’s nothing sweet and their fave local bakery is going out of business.
Similarly, tensions between nations might go dormant for a while--a peace treaty calms things down, perhaps--but if one diplomatic mission goes wrong, suddenly you have an arms race on your hands. These conflicts don’t necessarily have to be a part of your campaign arc; they can serve as flavor and offer you extra stakes so that players know there are consequences if they screw up this escort mission or cross the wrong border without permission. The PCs may get a biased version of these conflicts--tell them what they would likely have heard or believe, not necessarily the facts (propaganda and rumor is a helluva drug).
The short version of all this boils down to:
Give the players any information they ask for that you deem reasonable for them to know;
Actively conceal, downplay, or obscure information that might have plot implications in the future;
Prepare tensions, conflicts, and flavor details more than you actually prepare history, because PCs can’t interact with history; they can interact with the present-day legacy of that history.
