Dragonlance

Dragonlance is a shared universe created by Laura and Tracy Hickman, and expanded by Tracy Hickman and Margaret Weis under the direction of TSR, Inc. into a series of popular fantasy novels. The Hickmans conceived Dragonlance while driving in their car on the way to TSR for a job application. At TSR Tracy met Margaret Weis, his future writing partner, and they gathered a group of associates to play the Dungeons & Dragons role-playing game. The adventures during that game inspired a series of gaming modules, a series of novels, licensed products such as board games, and lead miniature figures.

The fictional Dragonlance world of Krynn contains numerous characters, an extensive timeline, and a detailed geography. Along with D&D's world of the Forgotten Realms, Dragonlance is one of the most popular shared worlds in fiction.

Source: Wikipedia, "Dragonlance", available under the CC-BY-SA License.