The first virtual worlds
In 1974, Mazewar introduced the first graphic virtual world, providing a first-person perspective view of a maze in which players roamed around shooting at each other. It was also the first networked game, in which players at different computers could visually interact in a virtual space. The initial implementation was over a serial cable, but when one of the authors began attending MIT in 1974, the game was enhanced so that it could be played across the ARPAnet, forerunner of the modern Internet.
You haven't lived until you've died in MUD. -- The MUD1
Adventure, created in 1975 by Will Crowther on a DEC PDP-10 computer, was the first widely played adventure game. The game was significantly expanded in 1976 by Don Woods. Adventure contained many D&D features and references, including a computer controlled dungeon master.
Inspired by Adventure, a group of students at MIT, in the summer of 1977 wrote a game called Zork for the PDP-10. It became quite popular on the ARPANET. Zork was ported under the name Dungeon to FORTRAN by a programmer working at DEC in 1978.
In 1978 Roy Trubshaw, a student at Essex University in the UK, started working on a multi-user adventure game in the MACRO-10 assembly language for a DEC PDP-10. He named the game MUD (Multi-User Dungeon), in tribute to the Dungeon variant of Zork, which Trubshaw had greatly enjoyed playing. Trubshaw converted MUD to BCPL (the predecessor of C), before handing over development to Richard Bartle, a fellow student at Essex University, in 1980.
MUD, better known as Essex MUD and MUD1 in later years, ran on the Essex University network until late 1987.
The popularity of MUDs of the Essex University tradition escalated in the USA during the 1980s when affordable personal computers with 300 to 2400 bit/s modems enabled role-players to log into multi-line Bulletin Board Systems and online service providers such as CompuServe. During this time it was sometimes said that MUD stands for "Multi Undergraduate Destroyer" due to their popularity among college students and the amount of time devoted to them.
In 1987, Nihon Falcom's Yoshio Kiya, creator of the Dragon Slayer action role-playing games, expressed his idea for an online RPG "with a system that allows total freedom for the player. For example, despite it being a sword and sorcery world, the hero decides to do nothing and just quietly enjoy his life as a local baker in town. If everyone could take up different roles in some kind of computer networked game, I think it would be really fun."
In 1989, Yehuda Simmons published Avalon: The Legend Lives which has seen continued development and support ever since. Avalon, while not the first MUD, certainly set the bar for imitators, boasting never-before-seen features such as fully fleshed out economics, farming and labour mechanics, player-driven autonomous governments with ministers, barons and organization elections, a fully realized warfare conquest system featuring legions, battalions, trenches, minefields, barricades and fortifications, as well as thousands of unique player abilities and skills which formed the basis of Avalon's meritocratic PVP system based on skill-worth as opposed to the traditional level-based progression system favoured by many other games of this genre. Avalon's mission statement was to be the first fully developed roleplaying world - a life within a life using real-world systems to fully immerse players into the lives of the characters they created.
Many MUDs are still active and a number of influential MMORPG designers, such as Raph Koster, Brad McQuaid, Matt Firor, Mark Jacobs, Brian Green, and J. Todd Coleman, began as MUD developers and/or players. The history of MMORPGs grows directly out of the history of MUDs.