Realms of the Unknown is a pencil and paper game where players take on the roles of Nobles or other leaders of a population. They give orders to their troops and population, explore, invade other territory, encourage population growth, etc. One player is the Realm Controller and sets up the Realm in advance, and gives the players the results from their orders. The game is structured in a way similar to PBM games in that the players hand in their orders each day for a time period covering 1 week in the game. There are rules for Population growth and characteristics; resources including livestock, mines, farms, logging, etc; Technology development, and combat. Combat involves a series of formulas taking in as many factors as possible including number and training of troops, armor, troop types, leaders, weather, terrain, and other factors. This results in a modified strength of each force. When these are compared the relative strength determine losses for each side as well as the victor in the battle.
The rules come in two books - Player's Manual and Realm Controller's Manual.
See also the roleplaying game listing Realms of the Unknown