You will need: lots of d6s, a hexmap of the region, a bunch of very small miniatures of at least 2 or 3 types and enough colors to differentiate the factions, pen and paper. I used Risk pieces for the miniatures.
USING THE SYSTEM
Give each settlement a population: I used 6 infantry chits and 2 cavalry chits for each. This is what all groups are drawn from. Each day, roll on the Settlement Behaviour Table for each settlement. Then, for each group out roll direction of travel. Each group type has different behaviour. There are two types of chit on the board: Cavalry and Infantry. When two groups meet and fight, roll a die for each chit. Every 5 or 6 indicates a removed enemy chit. Groups solely consisting of cavalry move two hexes per turn.
When two groups meet, roll a die. This contact determines the relationship between the two groups. If this is the first time they meet, a 1 means open war, 6 means an alliance between the two, a 2 or 3 means hostility (-1 to all future rolls), and a 4 or 5 means friendship (+1 to all future rolls.) If this is the second or later time, do not roll if there was a 1 or 6 previously, but do roll and apply modifiers if there was a 2,3,4, or 5.
If two groups are in adjacent hexes, there is a 50% chance that they will each move into the other group's hex. Similarly, if a group is next to a village, they will
- Set up a patrol (moves around the village and any farmland. Roll 1d6 for numbers: 1-4 means infantry equal to the number shown, 5-6 means 1 cavalry)
- Send out a hunting party (move at random. Roll 1d6 for numbers: 1-4 means infantry equal to the number shown, 5-6 means 1 cavalry)
- Send out Settlers (Roll d8. 1-6 move,7-8 create new settlement. Consists of 1-3 infantry.)
- Grow: gain 1 infantry chit if under 10 total chits, if 10 chits expand into adjacent hex and move 1/2 population.
- Shrink: Lose 1 chit if there is more than 2 chits in the village, otherwise lose a random expansion. If there is noone in the village and no expansions, village collapses and is removed
- Investigate: Moves on the 1-3 hexes that go toward a random town within 5 hexes.
This system works best in small, dense areas. I also recommend you put a small paper tag under each group stating origin and purpose. Additionally, you should probably name each village.