Imperium is a play-by-email wargame run by Email Games. The game is set in a fictional remote future where human beings have colonised the known galaxy and established a trading civilisation. Periodically, this civilisation erupts into war and major trading guilds (or houses) compete to re-establish their dominion. The major units of Imperium include ships, armies, and leaders and the major strategic elements include warfare, diplomacy, intelligence and planetary production. Typically, a game of Imperium will take 10–15 weeks to complete and involve 12-20 players, located across the world. Players submit one set of orders per week and engage in diplomacy and discussion via email.