I don't like the offical history for Athas, so do many others, but some do like the offical timeline. Each to his own 
but what is your preffered history?
My homebrewed history is based of several points:
In the Illithiad, 2nd ed book on the mind flayers, and some other place, it's noted that the Mind Flayers had a long standing desire to put out the Suns, as suns blind the illithids and removing them would shatter the power of humanoid races, making them easy prey and slaves.
So I decided that the Illithids on Athas had in times long past, decided to put out the Sun of Athas, but they screwed up, leaving it a red giant.
Athas has a LOT of psionics, where did that come from?
Where would the illithids get sufficent power to put out the Sun? I thought, well if they introduced psionics to many creatures, it would explain why psionics is common, and they secretly harvested some of that psionic power over a long time for their "sun darkening" attempt.
Athas has exhausted nearly all it's metal ore resources. Now that isn't easy to do, so to my mind, it's part of showing that Athas is INCREDIBLY old. Civilizations for maybe millions of years have mined out nearly all the ore.
There's little metal around but magic items and many metals have very VERY long lifespans, even acounting for the age of Athas, so where have they gone? The sou-uts gave me an idea. So-uts attack metal and buildings in prefference to any other target, which is very odd indeed, and they specifically have abilities to destory such (acid, supe rhard claws etc).
So I decided so-uts and other creatures had been designed as "scorched earth weapons", in some ancient war, one side decided that destorying the entire basis for civilization: buildings, metals etc, would wreck the enemy's ability to make war.
But since these were living creatures, they never stopped destorying, and thus metals and buildings were slowly and surely destroyed.!
And more new, terrible beasts kept emerging form the desert and even the people are not normal. in the official timeline a lot of those are caused by the Pristine Tower, many more are caused by the weird conditions on Athas.
I figured much the same, places where defilers' magic lingered, anicent battle sites reeking with poisons etc. Plus the Dark Sun itself and the great age of Athas (thus plenty of time for new mutants to arise)
An apocalyptic war tore across Athas aeons ago. defiling came about because of psionics that the illithids spread about, and some greedy mage discovered how to use pisonics to let his spells suck life force..these "defilers" soon became more powerful than normal wizards, and wars started which became total carnage.
Many mutated beasts were created as living wepaons, such as the so-uts, and civilizations began to fall because of the damage the deiflers did to the natural world, and the war and living weapons did to the resources humanoids required.
The sorceror Kings are the surviving defilers, or perhaps descendants, of that era...or maybe they are things far far removed from humanoids...
that's my Athas or at least what it MAY be, as things are so strange in that world
My version of Athasian history is the one I feel the bulk of material concerning Athas (from wthin and from other settings, like Planescape) supports and implies. The Grey was created by Ahriman (Asmodeus' ancient form and name) to absorb the souls of the faithless denizens of Athas. The Elemental Pacts were developed as a means to escape the fate of the Grey(Asmodeus' distended belly in a sense). The Elementals then can ork towards their goals for the Prime, and their devout clerics are transmigrated to the appropriate Inner Plane(or else, section of the Elemental Chaos in 4e). Asmodeus doesn't like competition for the souls therein, which he absorbs to restore his original body, after whic he will try to conquer the multiverse. It was a fiend who influencd Jamourille the Wis to tutor Rajaat in magic, knowing that when Rajaat arrived home, he would have to find a way to invoke magical effects, without drawing on the usual cosmological components of a spel. Thus, defiling as developed. And Ahriman said it was good. Psionics had already developed beforehand, another power source Ahriman rizd for its versatility and ability t function on any plane. Athas as a whole has no idea that Amodeus is farming them as his personal army of conques, alienand unstoppable. And ompletely different fromany force on would expect from any other plane. There isan ancient pact involved with ending the Primordial Wars, werein the Gods gave Athas to the Primordials as their sole refuge. They cordoned off te local space witha barrier t revent the gods from travelling there, or the primordials from escaping. And Asmodeus laughed as their machnationsdisqused the true nature ofthe grey, which before had been a featureless void. Now, the grey was Grey, and functioned as not just a soul-net, but a nearly mpenetrable barrier around his pantry Asmodeus has not reveaed the whol truth to his ally Dregoth, but plans to use hm to contl Athas for him, while granting Dregoth the illusion of freedom and independent action. Only the Primordials know the truth, and they despise the undead spawned by the energies of Asmodeus' foul maw, thus the ability of clerics on Athas to turn undead, for every undead is a piece of Asmodeus' influenceleft on Athas. Other dark gods have great interest in harvesting some of Asmodeus' liestock, and have sentLiving Conduits to pierce the grey and grant spells to their Athasian worshippers.
The common Athasian knows nothing of this.
Pretty bad*ss history. Did you just make that up. I don't recall anymore Rajaat's story beyong being a twisted Pyreen. But very cool and elaborate.
I always had the impression that metal was rare becuase the technology was lost.
I always had the impression that metal was rare becuase the technology was lost.
Pretty sure one of the boxed sets mentions it is rare because it was mined out during the Cleansing Wars. My stuff is buried in the closet or I'd try to go find the reference.
Raven is right: the Tyrian mine is said to be the last functionning iron mine of the Tyr region, and working it is a deadly job, what with explosive gases, heavy metal poisoning, and hej-kin attacks. It eats up slaves too fast.
I know a lot of you will disagree but I do like the history of Athas as is" (Blue, Green age etc.) Although I dont like what happened in the Prism pentad. Oh! And I could do without the Last Sea expansion box set: except for the fact that a scool of dolphins survived as well as some lizardmen. Lets not forget the Squark which I like the idea of it being an relic from the Rhulisti dynasty.
Jihun
Who needs metal anyway when you can just break your bone sword off in somebodies rear section.
I think the official history of Athas as it has been delivered is brilliant. No deities from the get-go, several distinct and concept-rich ages, a slow but steady degeneration of civilisation, lifeshaped-dependant societies, life-fuelled arcane magic, element-fuelled divine magic, etc etc.
What I find so appealing about the Athas' history is that I can see clear parallels with our own history. At least from the Green Age onwards. I don't mean to navel gaze for too long here, but bear with me.
Blue age and before: Rhulisti (spelling?) live in perfect harmony with their environment in a golden age of civilisation undreamed of to contemporary Athasian folk. Things are good, but perhaps not yet good enough. The life shapers get greedy and trigger the Brown Tide that puts an end to their epoch of supremacy, via the construction of the Pristine Tower used to detroy this cancerous accident. This chain of events makes me think of the Atlantis legends, depending on what sources you base their demise on. Both are wielders of great science despite living in times of great antiquity. But unlike the Atlanteans, they are not destroyed, but certainly diminished.
The Green Age is akin to our own Renaissance, a time of discovery and invention. Psionics and magic discovery and so on. Even some of the artwork in the original editions of Dark Sun Accessories feature ghosts of long ago whose garb smacks of early-to-mid Renaissance (look at Er'Thork in the Black Sand ruins featured in the Slave Tribes accessory).
Then you come to the Cleansing Wars. Powerful magic has been wielded to exterminate certain races seen as unfit to inhabit the planet for whatever reasons the perpetrators of this genocide feel is justifiable. Can anyone think of a similar analog in our own history? Here's a hint: it involved a political socialist party with a penchant for 'racial hygiene' and the occult (Well, certain members) in the early part of the 20th century.
Furthermore, the very magic wielded to destroy these unfortunate races itself destroys the land in the name of accomplishing its wielders' will. In our own world I can see this as the gears of industry grinding out technological advances at the cost of the environment it depends on to do so. One world war leads to another, technology becomes ever more destructive, until we come to the present where we have the means of annihilating ourselves and everything else through nuclear, biological and other means.
The original Dark Sun boxed set was published in 1991, so was probably worked on during 1989-1990 (speculating here of course). Anyone that was around back then will remember that the whole issue of pollution, the hole in the ozone layer above Antarctica and the greenhouse effect (wasn't called climate change back then) was being taken seriously by the media after years and years of forewarning by climatologists.
Of course, present day Athas is a glimpse of where we might live if we don't watch ourselves and allow 13 champions to wipe us out in the name of some Rajaat or another.
Oh and in my history I liked to fill in some gaps. One example is that a lot of the iron in Athas was devoured by summoned xorn and magically created rust monsters - which like the bioweapons of sci-fi died without procreating once their task was complete. This was so the armies of the races that were being systematically exterminated could not equip themselves en masse to thwart the defilers and their hordes.
Remember that the techniques employed by contemporary Athasians to make do without metal didn't reach the level of utilitarian sophistication it is now overnight. It took centuries to develop. Well, in my campaign anyway. 