1st edition D&D generally revolves around the world as set forth in Gygax's "World of Greyhawk, as outlined in the World of Greyhawk Gazetteer. It's a place which takes up 1/4 to 1/3 of the known "Oerth", with plenty of politics and TSR/WotC published scenarios taking place within it.
Although I'm keen to incorporate some of the classic 1E modules into a new campaign, I'm not so sure I want to bring Greyhawk itself into it. For one, I like the challenge of designing my own world, not to mention the delusions of godhood it affords me... but this type of thing is a lot of work for it to be done to my satisfaction. Fleshing it out as we play along, as it becomes necessary, seems the most energy conserving route. Most if not all of the old TSR modules should be able to be lifted and divorced from the Greyhawk setting, with place names and directional references simply replaced or omitted for purposes of clarity.
I'm curious as to what others have done in this regard though, esp. those that have only returned to the game after being away for years (or decades such as in my case!). I am aware of other commercially released campaign settings, such as Forgotten Realms, Dragonlance, & Ravenloft, but am more intrigued by OGL material like Kingdoms of Kalamar. Ironically, I'm very drawn to the type of portrait described by the Points of Light settings, laid out by WotC in 2005 as 4E was approaching.
In the Points of Light setting (in a nutshell), "Civilized folk live in small, isolated points of light scattered across a big, dark, dangerous world." Where "...Adventurers are aberrant. Commoners view them as brave at best, and insane at worst...but such a world is rife with the possibility for adventure, and no true hero will ever lack for a villain to vanquish or a quest to pursue."
This is the type of general setting which I could immediately begin a game in, and then fill out as need be. Unfortunately, as near as I can gather, this world was never more fully described or published. Still, perhaps that was the whole point!
A fun sounding OGL alternative written by Mike Stewart at Dragonsfoot.org is Aedenne. The author describes it as follows: "In Aedenne, magic is a powerful factor in the world but not usually seen by the general populace. The realms are emerging from a 'Dark Ages' after the fall of the Imperium; much as western europe did the same after the fall of Rome."
"The usual antipathy between Dwarves and Elves is unknown in Aedenne. Granted, there is little affection lost between the two but no real hatred. Humans and Elves are where the true enmity lies. Humans dislike the Elves due to their power, their airs of superiority, and the occasional Elven attempts to subjugate them. Elves disdain Humans as short-lived, brutish folk little higher than the Orcine races. They also secretly envy the Humans as they know that Humanity are the future while they are the past; eminently adaptable while Elvenkind is rigid and unchanging in their semi-immortal state."
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