[6] In 1980, Roy Trubshaw created MUD version 3 in BCPL (the predecessor of C), to conserve memory and make the program easier to maintain.

[8] Richard Bartle, a fellow Essex student, contributed much work on the game database, introducing many of the locations and puzzles that survive to this day.

Later that year Roy Trubshaw graduated from Essex University, handing over MUD to Richard Bartle, who continued developing the game.

[14] Trubshaw and Bartle (with the assistance of Simon Dally) subsequently formed the company Multi-User Entertainment Limited, and proceeded to work on MUD version 4, also known as MUD2 (released in 1985).

This left MIST, a derivative of MUD1 with similar gameplay, as the only remaining MUD running on the Essex University network, becoming one of the first of its kind to attain broad popularity.