BatMUD

BatMUD was started by students in Finland in 1990, in the same wave that spread LPMud servers across university networks. Players connected over Telnet to a fantasy realm described entirely in text, with races, classes, guilds and an elaborate path to becoming a wizard and building parts of the world yourself. As in most MUDs, the players wrote much of the content.

What sets it apart is stamina. Most MUDs of that era vanished when their students graduated or the university wanted its machine back, but BatMUD moved to its own hosting and has run continuously for more than thirty years. The graphics never arrived, and that is not an oversight.