MUD Family Tree

AberMUD was first written in 1987 in the B language by Alan Cox, Richard Acott, Jim Finnis and Leon Thrane at the University of Wales, Aberystwyth (after which it is named), on a Honeywell mainframe; its gameplay was heavily influenced by MUD1, which Cox had played. In late 1988 Cox ported it to C to run on Unix at Southampton University, producing AberMUD2, and by 1989 instances ran across the UK. Later versions (IV and V, c. 1991) were released under the GNU GPL. Its portability and free availability made it a major influence on LPMud and DikuMUD.

Monster was written by Richard Skrenta at Northwestern University in 1988, in Pascal for VAX/VMS. Rather than a client-server design, each player ran a separate copy of the game sharing a common on-disk database. Monster was notable as one of the first multi-user games to let administrators build the world from within the game: online creation of rooms, objects and puzzles. Skrenta released the source on the Usenet group comp.sources.games in November 1988. Though never widely deployed, it was the direct inspiration for James Aspnes's TinyMUD.

MUD1 (Trubshaw & Bartle, Essex 1978) was licensed to CompuServe in the United States, where it ran as British Legends from 1987 until CompuServe retired it around 1999. This is the original MUD continued commercially: the same Bartle/Trubshaw heritage as the open-source tree's root, but a separate, closed line rather than a feeder of the AberMUD descendants.

Island of Kesmai launched on CompuServe in 1985, developed by Kelton Flinn and John Taylor of Kesmai, building on their earlier Dungeons of Kesmai (c. 1980). A paid, roguelike-style multiplayer world charged by the hour, it is frequently cited as the first commercial MMORPG and ran on Kesmai's own software, independent of the open MUD codebases. Kesmai was bought by News Corp (1994), sold to EA (1999), and the games were shut down around 2000–2001.

GemStone III launched on the GEnie online service in 1990, developed by Simutronics on their in-house Interactive Fiction Engine (IFE), written in C. It continues today as GemStone IV (since 2003), carrying its world and characters forward, and is frequently cited as the longest-running commercial MUD. The engine is proprietary and unrelated to the open codebases. (Its game rules originally licensed Iron Crown's Rolemaster system, which was removed by the mid-1990s: a rules licence, not a code lineage.)

Darkness Falls began as the BBS game Tempest by Interesting Systems, evolving into a three-realm PvP text MUD; Mythic Entertainment was formed in 1995 from the merger of Interesting Systems and Mark Jacobs's AUSI. The successor, Darkness Falls: The Crusade, ran on AOL and the web from 1999 until it closed around early 2006. Its realm-vs-realm design and server became the basis for Mythic's graphical Dark Age of Camelot. The engine was Mythic's own, independent of the open codebases.

Achaea launched in 1997, the flagship of Iron Realms Entertainment (founded by Matt Mihaly). It runs on Iron Realms' in-house Rapture engine (after the earlier Hourglass and Vortex), which powers all of the company's worlds. Rapture is a custom engine rather than a fork of any open codebase, so Achaea is genre-influenced by the Diku and LP traditions but not code-derived from them.

Created in 1993 by Paul Barnett and Doug Goldner and launched on AOL (UK 1995, US 1996), Terris, later Legends of Terris, was for several years among AOL's most-played games before moving to the web with a custom front-end. It runs on Goldner's custom 'Horizon Engine', independent of the open codebases. Its current operational status is unconfirmed.

The Eternal City launched in 1996 (Worlds Apart Productions) and is now operated by Three Seas LLC, remaining active. It runs on Worlds Apart's own game system built on Cold/Genesis: the ColdC language, descended from ColdMUD, an object-oriented server in the MOO lineage. Skotos published and hosted TEC from 2001 under license, but unlike Skotos's own DGD-based SkotOS games (such as Castle Marrach) it kept its ColdC/Genesis engine rather than being ported. Because that engine is itself an open codebase in this tree, TEC is the closest the commercial branch comes to the open-source lineage.

Castle Marrach was Skotos Tech's first and flagship multiplayer interactive-fiction game, opening its beta in 2000 on the company's SkotOS library (which runs on Felix Croes's DGD, an LPMud-family driver). It emphasised mandatory, prose-based social roleplay: characters awaken from a kind of cold storage with lost memories inside the Castle, interacting with other players and with StoryTellers. It was the largest SkotOS-based game; after Skotos Tech wound down around 2020 it was among the games spun off to continue independently.

Dragon's Gate was developed by Adventures Unlimited Software (AUSI), founded by Mark Jacobs, with its core based on AUSI's earlier game Aradath (designed by Jacobs around 1985) and co-developed with Darrin Hyrup. It opened to the public on GEnie in spring 1990, moved to AOL in 1996, and finally ran on an independent server until it closed on 10 February 2007, one of the longest-running pay-to-play text MUDs. AUSI's lineage leads to Mythic Entertainment (formed 1995 from Jacobs's AUSI and Rob Denton's ISI), which also made Darkness Falls and Dark Age of Camelot.

Federation traces to 1985, when Compunet ran the 'Multi-User Galaxy Game' as a science-fiction alternative to MUD1; when a programmer left, Alan Lenton rewrote it from scratch as Federation II (there was no Federation I). It opened on 10 January 1988 on Compunet (cited as the first MUD with a non-fantasy setting), moved to GEnie in 1990 and AOL from 1995, then ran on the web under ibgames. The original game closed on 1 October 2018 after roughly 30 years; a community revival (Federation 2) continues with Lenton's blessing using ibgames' released source.

MajorMUD was created by West Coast Creations (WCC), a Canadian group led by Lance and Cathy Neumann. It was released on 4 November 1994 as a paid third-party module for Galacticomm's The Major BBS / Worldgroup bulletin-board platform, and became one of the most popular commercial door games of the BBS era. WCC sold the game to Metropolis Gameport in 1999; Metropolis shut down around 2008. The game survives through retro BBS systems and the MBBSEmu emulation project, which runs the original Worldgroup module on modern hardware.

Threshold RPG was created by Michael A. Hartman ('Aristotle') and launched on 17 June 1996, the same year he founded the studio Frogdice. It is written in LPC (the language of the LPMud family), but its operators describe it as a custom code-base rather than a stock LPMud or DikuMUD distribution. Strongly roleplay-enforced, it has run continuously for roughly three decades and ranks highly on listings such as Top Mud Sites and The Mud Connector. Whether it forked a specific driver/mudlib or was written from scratch is not firmly documented.

Avalon: The Legend Lives was written by Yehuda Simmons and first released on 28 October 1989, coded in a bespoke language on an Acorn Archimedes; Daniel James joined development around 1990. It went independent in 1990 and became pay-for-play in 1994. It is frequently described as the first MUD to combine a consistent fantasy storyline with a commercial venture, and ran for decades as one of the longest continuously running online role-playing games, with regular outages beginning around 2023. (It is not the first commercial multiplayer game overall: Island of Kesmai, 1985, predates it.)

Shades was begun at Christmas 1985 by Neil Newell, a MUD1 player who started writing his own MUD when MUD1 was shut down over the holidays; though inspired by MUD1 it was original code, not a derivative. It became a commercial MUD via British Telecom's Prestel and Micronet 800 networks, one of the earliest pay-to-access multiplayer text games in Britain. Its chief rival on the same platform was Gods, by Ben Laurie. A scandal involving Shades is recounted in Indra Sinha's memoir 'The Cybergypsies'. Its commercial life ended when BT closed Micronet on 31 October 1991.