Several commercial versions were also released such as Empire: Wargame of the Century, often adding basic graphics to the originally text-based user interface.

Walter Bright created Empire as a board wargame as a child, inspired by Risk, Stratego, and the film Battle of Britain.

He ported Empire to assembly language on a Heathkit H11 ("If I'd had a brain, I'd have bought an Apple II") and made it available commercially in 1983.

In 1983 Bright contacted DECUS, who credited him in the catalog description of the program and source code;[4] many players became aware of the game from this version.

[8] In 1984, Bob Norby from Fort Lauderdale, Florida, ported the DECUS version from the VAX to the PC as shareware.

In 1987, Chuck Simmons re-implemented the game in C using the UNIX curses library in order to make use of its support for many different character-cell terminals.

Starting around 1987, Empire: Wargame of the Century on the Atari ST, Amiga, Commodore 64, Apple II, Macintosh, and MS-DOS was produced.

[citation needed] In the early 1990s, Mark Baldwin and Bob Rakowsky rewrote the game, calling it Empire Deluxe[12] for DOS, Mac OS, and Windows, released in 1993 with New World Computing as the publisher.

[citation needed] An expansion pack, Empire Deluxe Scenarios, was produced later in 1993, including a map and scenario statistics tool, a map randomiser tool (as random maps were present in the Interstel version, but lacking from Empire Deluxe), upgrade patches for both DOS and Windows versions and a collection of 37 scenarios (with accompanying maps) from "celebrity" designers, many of them famous in the games industry including Will Wright, Jerry Pournelle, Jim Dunnigan, Johnny Wilson (Computer Gaming World editor), Gordon Walton, Don Gilman (Harpoon series architect), Trevor Sorensen (Star Fleet series designer), and the game's authors Mark Baldwin and Bob Rakosky.

This was essentially a port of the code Baldwin and Rakowsky produced in 1993, with few changes, such as a slightly increased map size (255×255), but did not add any new rules.

The game editor feature was enhanced by allowing the user to design not only new maps and campaigns, but also new units with new graphics and sounds.

There are ports and source code for modern PC operating systems available for free download at Walter Bright's Classic Empire webpage.