Initial hostilities were provoked by the evil demigod Iuz, but rapidly expanded to cover most of the Flanaess as opportunistic nations used the conflict to further their own ends. This conflict saw the unification and expansion of the Orcish Empire of the Pomarj as well as a desperate attempt by the Great Kingdom to reclaim its former glories.
The wars were ended in 584 when the final truce was brokered in the Free City of Greyhawk, and the wars have come to be named for the city as a result.
In the late 1980s, TSR, the publisher of Dungeons & Dragons, had been disappointed by declining sales of the Greyhawk product line. TSR therefore decided to make a significant change to the setting to re-invigorate customer interest and sales of Greyhawk-related materials. The Greyhawk Wars were the in-game catalyst used to allow TSR game developers, principally Carl Sargent, to take the setting in a new direction.
The storyline leading up to the Greyhawk Wars is presented in the 1991 adventure modules Five Shall Be One and Howl from the North (WGS1 and WGS2). These modules were intended to enable Dungeon Masters to involve their players in the events that precipitate the start of the Wars.
TSR published the history of the Wars themselves in the "Greyhawk Wars Adventurer's Book," which was included as a component of David Cook's 1991 board game Greyhawk Wars. The game allowed participants to play the events of the Wars as a strategic simulation, controlling various political entities, military units and heroes of the World of Greyhawk in competition with other players.
Meanwhile, Carl Sargent had been working on a significant update for the World of Greyhawk campaign setting as a whole. This was published in 1992 as a boxed set entitled From the Ashes. The boxed set detailed the situation on the Flanaess in the aftermath of the Greyhawk Wars. From the Ashes was followed in 1993 by a series of Sargent sourcebooks and modules providing additional information regarding the updated setting, including The Marklands, Iuz the Evil, and City of Skulls.
The tone of Sargent's post-Wars material was intentionally darker and more grim than pre-Wars TSR publications. These changes generated mixed reactions from fans of the setting, failed to sufficiently revive sales, and led to TSR's cancellation of the product line in late 1993.
- Cook, David. "History of the Greyhawk Wars." Wars. Lake Geneva, WI: TSR, 1991. Available Online: 
- Henson, Dale. Howl From the North. Lake Geneva, WI: TSR, 1991.
- Holian, Gary, Erik Mona, Sean K Reynolds, and Frederick Weining. Living Greyhawk Gazetteer. Renton, WA: Wizards of the Coast, 2000.
- Sargent, Carl. "Campaign Journal: The Adri Forest." Dragon #208. Lake Geneva, WI: TSR, 1994.
- -----. "Campaign Journal: The Sea Barons." Dragon #206. Lake Geneva, WI: TSR, 1994.
- -----. The City of Skulls. Lake Geneva, WI: TSR, 1993.
- -----. "Fiend Knights and Dark Artifacts." Dragon #206. Lake Geneva, WI: TSR, 1994.
- -----. Five Shall be One. Lake Geneva, WI: TSR, 1991.
- -----. From the Ashes. Lake Geneva, WI: TSR, 1992.
- -----. "Greyhawk Campaign Journal: Risen from the Ashes." Dragon #191. Lake Geneva, WI: TSR, 1993.
- -----. Iuz the Evil. Lake Geneva, WI: TSR, 1993.
- -----. Ivid the Undying. Lake Geneva, WI: TSR, 1995 (unpublished). Available online:
- -----. The Marklands. Lake Geneva, WI: TSR, 1993.