The Endless Fire destroyed the city of Mareilon in 773 GUE and set back the public's acceptance of magic. This magical inferno, kindled on the 18th of Estuary was so named because it burned for 4 weeks after consuming Mareilon. A well-meaning local civil servant caused the unspeakable devastation when he attempted to cast the ZEMDOR spell (“turn original into triplicate”) but, instead, accidentally cast the ZIMBOR spell instead (“turn one really big city in lots of tiny, little ashes”). He reportedly apologized to the city, with the words: “Whoops! My bad!”

Lord Dimwit Flathead the Excessive’s response was swift and characteristically extreme. The Endless Fire led him to issue a series of 5,521 edicts over the following few weeks, which had the effect of severely limiting public access to magic (and, incidentally, lawyers). Henceforth, all magic was entrusted to the various Guilds of Enchanters.

SOURCE(S): Enchanter (A Brief History of Magic), Zork: Grand Inquisitor, various others