From the publisher:
You and any number of friends will take control of an entire fantasy world. Dividing the map equally and working together you will create unique landmasses, geography, and resources for your world. From there each player will take command of a major faction and develop it from a struggling settlement to a massive empire, or perhaps drive it into the lost histories of time.
Each player will take turns rolling the dice and placing features in their section of the map. Each of these regions will be home to one empire and throughout the game each player will create the story of the major empire within their play area. They will roll to decide many aspects of this empire but much of the story and design will be up to each player’s imagination.
Mappa Imperium is first and foremost a cooperative storytelling game and is played best when the players work together. By the end of the game you will have a full fantasy map complete with empires, lore, hostile tribes, and mysterious lairs.