I'm guessing this perhaps was one of the sources.

https://mud.fandom.com/wiki/MUD1

MUD1 (referred to as MUD1, to distinguish from its successor, MUD2) is the oldest virtual world in existence. It was created in 1978 by Roy Trubshaw at Essex University on a DEC PDP-10 in the UK, using the MACRO-10 assembly language. He named the game Multi-User Dungeon, in tribute to the Dungeon variant of Zork, which Trubshaw had greatly enjoyed playing.[1][2] Zork in turn was inspired by an older text-adventure game known as Colossal Cave Adventure or ADVENT.[3]


John H. Reinhardt


On 3/20/2026 12:56 PM, Johnny Billquist via groups.io wrote:
The article is pretty bad. :-(
In multiple ways.

  Johnny

On 20/03/2026 18.52, Paul Koning via groups.io wrote:
Oh.  The article gave the meaning of MUD as "multi-user game", I missedthe mismatch.

Multi-user dungeon games were among the most popular multi-user games on PLATO at least as far back as 1976 and probably earlier.  They still are, in fact.

    paul

On Mar 20, 2026, at 1:42 PM, Johnny Billquist via groups.io <bqt=softjar.se@groups.io> wrote:

Well, to be nit-picky - MUD = Multi User Dungeon. :-)

For sure it was nowhere near the first multi-user game in general. Notsure I head of any earlier MUDs though...

  Johnny

On 20/03/2026 18.38, Paul Koning via groups.io wrote:
On Mar 20, 2026, at 1:16 PM, Jon Morgan via groups.io <jmorgan6=gmail.com@groups.io> wrote:

(Apologies for the cross-posting.)

  I very good friend of mine has been doing some digital archaeology.

https://infosec.exchange/@lorry/116257448642523972

I think a lot of folks here would like what he’s done.

                 -jon.
Interesting.  I see "wrote the first online multi-user game (MUD) on Essex University's DECSystem-10 in 1978".
That can be parsed several ways.  I assume it means "first on a DEC-10".  It certainly isn't the first MUD; there were probably a dozen different ones before then on the PLATO system.  In 1976 I remember airfight (multiuser flight / air combat simulator), empire (multiuser SF game in a Star Trek theme universe), spasim (SF game with 3d graphics), at least oneand possibly several DND games, and I'm sure there were several more I never knew or forgot about.  And all those were graphical games, not just text.
    paul