AberMUD

AberMUD was the first popular open source MUD. It was named after the town Aberystwyth, where it was written. The first version was written in B by Alan Cox, Richard Acott, Jim Finnis, and Leon Thrane based at University of Wales, Aberystwyth for an old Honeywell mainframe and opened in 1987.

The gameplay was heavily influenced by MUD1, created by Roy Trubshaw and Richard Bartle at the University of Essex, which Alan Cox had played.