Walter Bright originally started development of Empire in 1973, and the game saw its first release on PDP-10 computers in 1977. The Wargame of the Century version released in 1987 featured an updated UI and graphics, which were further improved upon in the 1993 release Empire Deluxe.
The game is presented from a top down perspective with a world map and is turn based, players start the game in control of one city and use this city to build armies to conquer other cities. The goal is to eventually take over the world.
The exact era of the game is unspecified, but the player can construct infantry, battleships, planes and submarines implying a somewhat contemporary setting.
Sid Meier has cited Empire as one of his major inspirations (along with the board game Risk) for his long-running Civilization franchise, and part of the planning for the Civilization series started with making a list of features he would like to add or change in Empire in order to make it a better game.