randomly generate aeons of warring empires

In this post, I use Mediterranean history to create charts that randomly generate plausible history. If you want to skip the numbercrunching, here are the charts:

1: Each century, for each already-existing empire, roll 1d4:
1-3: It continues to be important.
4: It dissolves or becomes unimportant.

2: How many new empires arose this century? Roll 1d6.
1-2: 0
3: 1
4: 2
5-6: 1d4

What does a plausible fantasy history look like? In order to feel familiar, it should avoid the monolithic extremes of 30,000 years of barbarism of Isaac Asimov’s Foundation and the 1000 generations of peace of Star Wars’ Old Republic. Better to stick to something more like Earth history: constantly changing borders as competing empires rise and fall. Not only does this feel more realistic, it lends itself better to D&D play. A big pool of fallen-empires-of-the-week provides diverse dungeons and treasure.

I decided that, to better determine what imperial histories look like, I’d count up a representative sample of Earth empires: How many exist side-by-side, and how often do they arise? From there, I could extrapolate random charts to generate my own game worlds. I limited myself to the Mediterranean from 500 BC to 1500 AD (after iron and before the New World). This is a manageable piece of the world. The Mediterranean is fairly easy to travel, so co-existing empires can interact. Furthermore, it provides the history many of us are familiar with.

Empires of the Mediterranean, 500 BC to 1500 AC

(A lot of data is from http://en.wikipedia.org/wiki/List_of_largest_empires. Specific dates are arguable, but I’m just trying to get a rough count here.)

How long do empires last?

It looks like empires have a half-life of a little more than 200 years: of the 27 Mediterranean empires, half (14) are dead after 200 years, 8 more after another 200, and 4 more after another 200. Only the Byzantine empire defies the odds for 1200 years. You’d be pretty close to accurate if you said that each empire has a 3 in 4 chance of surviving each century.

How often do empires start?

In the 21 century-marks I examine, 7 see the birth of 0 empires, 6 see 1, 5 see 2, 2 see 3, and one exciting century (1200) sees 4 empires arise. Here’s a d6 chart that models that pretty closely.
1-2: 0 new empires
3: 1
4: 2
5-6: 1d4

How big is each empire?

That’s extremely variable, even over the course of a single empire’s lifetime. Most empires reach their height around the middle. The Macedonian empire started small, conquered all of the Mediterranean overnight, and then shrunk again. The Bulgarian empire, on the other hand, is donut-shaped: it started at a decent size, disappeared briefly when it was conquered by the Byzantines, and then re-established itself. Therefore, I won’t make any dice charts for this one. Look at your campaign map and see what fits where. Generally, if an empire shares the world with many rivals, it’s probably smaller, and if it’s alone, it probably spans the known world.

The final empire-building model:

For every 100 years of ancient history, roll on the following tables.

1: Each century, for each already-existing empire, roll 1d4:
1-3: It continues to be important.
4: It dissolves or becomes unimportant.

2: How many new empires arose this century? Roll 1d6.
1-2: 0
3: 1
4: 2
5-6: 1d4

Differences between the Mediterranean and your campaign world: Monsters and magic!

Your campaign world is probably wilder than ancient and medieval Mediterranean, which should reduce the rise of empires. On the other hand, magic increases each country’s logistic and military might. People must compete for land with monsters, which reduces their imperial resources – but on the other hand, monsters can start their own empires. Let’s say that these opposing factors cancel out. Just make sure that a few of your empires are ruled by demi-humans, humanoids, or monsters. In my campaign world, I’d expect humans to be the major empire-builders. Obviously I have no real-world numbercrunching to do here, so I will just make up an extra, top-of-my-head d6 chart:

Who rules each new empire? Roll 1d6 for each new empire.
1-4: human
5: humanoid or demihuman (orc, elf, etc)
6: monster (vampire, lich, etc)

OR you can just play a game of Small World.

Edit: Gallowglas wrote a sweet random empire generator using these rules. I tried it a few times, and it works great, and I saw some interesting history unfold! Thanks!

13 Responses to “randomly generate aeons of warring empires”

  1. I love this, but it seems like you need to know at least two things before starting:

    1) How many centuries of history are we going to have?
    2) How many empires were there at year zero?

    I’m going to do this right now for my current novel, which lacks a good ancient history. I’m assuming 20 centuries, and 2 empires to start.

  2. Also, it would be cool to have some kind of mechanic under which a defunct or unimportant empire can come back, like the Bulgarians.

  3. paul paul says:

    Good points, William. When I ran this simulation, I started with 0 empires, and ran 2000 years. In different runs, I got very different histories, from worlds chock-full of little empires to worlds dominated by 2 or 3 empires at a time. I’d say 0 (barbarism) or 1 (monolithic empire) are the two most common starting places for fantasy history.

    I think that quirks like the Bulgarians are part of the embroidery you need to do to turn the die-rolls into history. When you roll up each new empire, you need to place and name it, and you can well decide that it’s an older empire reborn. These rolls should really be though of as prompts that help you stay within plausibility and guide your creativity. For instance, when every empire ends, what happens to it? is it conquered? does it dissolve in a civil war? Is it frozen in time? does its continent sink? does it set off a magical disaster? Do all the soldiers and generals take ship and set sail to the west, never to be seen again?

  4. Zeno says:

    Finally got to play a game of Small World this past weekend. I find the last comment very accurate xD

  5. Very cool. I just did this myself with a spreadsheet and an internet dice roller, starting with 0 empires and 2,000 years just like you. Got a very fun little history, with 25 empires total, including one monster empire that lasted more than 1500 years. Neat to see patterns emerge out of the randomness.

    So how do you run these simulations? Did you write a little program, or just roll a ton of dice?

  6. ranthoron says:

    Cool! I can’t wait to see those as business cards…

  7. paul paul says:

    For when you need to generate ancient empires while you’re ON THE GO!

  8. Jon says:

    It’s totally worth trying Dwarf Fortress to see how deep down the rabbit it goes modeling the history of the world using systems like this. Creating a new game can take 30 minutes of CPU crunching.

    Then you use a program called “Legends Viewer” to browse the exported world data. A sample:


  9. Gallowglas says:

    A random lurker here. I had some free time earlier this week, and threw together a little Javascript app automating this empire-generation process; thought it couldn’t hurt to share:


  10. Michael (Gronan) Mornard says:

    Sweet! I’ma steal!

  11. paul paul says:

    Gallowglas, nice!

  12. Brett Slocum says:

    If anyone has made a Random Empire Disaster/Denouement table, I’d love to see it.

  13. Wow, Free Guide To SWTOR, it sure is nice of you to drop a comment in here to let Paul know that his site “looks just like excellent.” Please, tell us more.

Leave a Reply