[4][5] Oerth has an axial tilt of 30 degrees, which causes greater seasonal temperature variation than on Earth and is controlled by wizardly and divine magic that shifts weather patterns to be more favorable to the populace.

[15] In the late 1960s, Gary Gygax, a military history buff and pulp fantasy fan, was a central, founding figure in the Castle & Crusade Society.

[15] Two of his children, Ernie and Elise, were the first players,[32] and during their first session, as Tenser and Ahlissa,[31]: 99  they fought and destroyed the first monsters of the Greyhawk dungeon; Gygax recalled them as being either giant centipedes[33] or a nest of scorpions.

By the time he was finished, the complex labyrinth encompassed thirteen levels filled with devious traps, secret passageways, hungry monsters, and glittering treasure.

[87] In the first issue of The Dragon published in June 1976, Gygax prefaced Chapter 1 of his serialized novella The Gnome Cache with a note that the story's setting, Oerth, was very similar to Earth in terms of geography.

[12] Gygax gave only the most basic descriptions of each state; he expected that DMs would customize the setting in order to make it an integral part of their own individual campaigns.

[95] His map included arctic wastes, desert, temperate forests, tropical jungles, mountainous cordillera, seas and oceans, rivers, archipelagos and volcanoes.

[95] Before the folio edition was released, Gygax planned to publish supplementary information, using his column "From the Sorcerer's Scroll" that appeared on a semi-regular basis in TSR's Dragon Magazine.

[117] A few months later, he published a five-part series of articles in the November 1982 through March 1983 issues of Dragon that outlined a pantheon of deities custom-made for humans in the world of Greyhawk.

However, the new availability of information about Gygax's campaign world and TSR's desire to make it central to Dungeons & Dragons encouraged many new writers to set their adventures in Greyhawk.

According to game designer Jim Bambra, "the second edition was much larger than the first and addressed itself to making the World of Greyhawk setting a more detailed and vibrant place".

However, by this time, Gygax was in Hollywood on a semi-permanent basis, approving scripts for the Saturday morning Dungeons & Dragons cartoon series and trying to land a deal for a D&D film.

The novel was designed to promote sales of the boxed set by providing colorful details about the social customs and peoples of various cities and countries around the Flanaess.

Five were written or co-written by Gygax, and the other three were from TSR's United Kingdom division: Both of the EX adventures, although nominally set in Greyhawk, transported characters through a planar gate into an alternate reality.

From 1983 to 1985, the only notable supplement for the Greyhawk world was a five-part article by Len Lakofka in the June–October and December 1984 issues of Dragon that detailed the Suel gods who had been briefly mentioned in the boxed set.

Rather than continuing forward with Gygax's plan for an entire planet, the setting was never expanded beyond the Flanaess, nor would other authors' work be linked to unexplored areas of the continent Oerik.

[132] In 1986, in the months following Gygax's ousting, TSR turned away from development of Greyhawk and focused its energies on a new campaign setting called Forgotten Realms.

The puns and jokes often referenced modern culture—the Amazing Driderman, King Burger, Bugsbear Bunny, and the crew of Star Trek—and the module also included an appearance by Gygax's Mordenkainen in a film studio.

The contents were designed to give Dungeon Masters ideas and play-opportunities unique to the Greyhawk world, including new monsters, magical spells and items, a variety of geographical features, profiles of prominent citizens, and the avatars of deities.

Written by Carl Sargent and Rik Rose, this was not the city created by Gygax and Kuntz, but a new plan built from references made in previously-published material.

In addition to Mordenkainen, seven of the wizards were previously existing characters from Gygax's original home game: Bigby, Otiluke, Drawmij, Tenser, Nystul, Otto, and Rary.

In addition, Sargent and Rose took Gygax's original Obsidian Citadel, re-purposed it as Mordenkainen's castle, and placed it in an unspecified location in the Yatil Mountains.

How else to explain a setting that encompasses everything from the somber A1-4 Scourge of the Slave Lords adventure to the King Kong-inspired WG6 Isle of the Ape to the cornball humor of WG7 Castle Greyhawk?

The main story vehicle would be a war fomented by an evil half-demon named Iuz that involved the entire Flanaess, which would allow TSR to radically alter the pattern of regions, alliances, and rulers from Gygax's original setting.

[143] Sargent tried to generate interest for this grimmer vision of the Flanaess by following up with an article in Dragon's March 1993 issue, writing, "...the powers of evil have waxed strong.

The year 1999 marked twenty-five years since the publication of the original Dungeons & Dragons rules, and WotC sought to lure older gamers back to Greyhawk by producing a series of nostalgia-tinged Return to... adventures that evoked the best-known Greyhawk modules from 20 years before, under the banner 25th Anniversary of D&D: In conjunction with the publication of the Return to adventures, WotC also produced a series of companion novels known as the Greyhawk Classics series: Against the Giants,[152] White Plume Mountain,[153] Descent into the Depths of the Earth,[154] Expedition to the Barrier Peaks,[155] The Temple of Elemental Evil,[156] Queen of the Demonweb Pits,[157] Keep on the Borderlands,[158] and The Tomb of Horrors.

At Gen Con 2007, WotC announced that the 4th edition of Dungeons & Dragons would be released the following spring, and Greyhawk would no longer be the default campaign setting under the new rules system.

After Gygax left TSR in 1985, he continued to write a few more Gord the Rogue novels, which were published by New Infinities Productions: Sea of Death (1987), City of Hawks (1987), and Come Endless Darkness (1988).

By the time Gygax and Kuntz had stopped working on the original home campaign, the castle dungeons had encompassed fifty levels of maze-like passages and thousands of rooms and traps.

Later that year, Troll Lord Games also published Castle Zagyg: Dark Chateau, an adventure module written for the Yggsburgh setting by Rob Kuntz.