The stories occur in the world of Greyhawk, also known as Oerth. This is the oldest official AD&D gaming world, invented by Gary Gygax and others in the 1970s, and is currently a trademark of Wizards of the Coast. The best-known and -explored continent on Oerth is called Oerik; near the center of this landmass is the Free City of Greyhawk, a metropolis where many adventures begin and many adventurers converge. Outside the Free City can be found over a hundred independent kingdoms, cities, forests, mountain ranges, oceans, deserts, and wastelands. These areas span more than a thousand miles in any direction; some are ruled by friendly forces, others by hostile ones, and a few aren't ruled at all. It is in this world that the Adventurers roam, battling foes, fulfilling quests and building kingdoms.