For thousands years there had been stories in the old world of strange disappearances, of people and ships vanishing with no trace. Most of the time this was attributed to an unfortunate event or particularly ravenous sea creature, but tales of other worlds, other planes of existence abounded. Usually these stories were silenced, often brutally in the Empire where talk of other worlds was usually a sign of Chaos taint to ardent witch hunters, but in fact, the stories were true.
The Elves and the Lizardmen knew of Palurin, for the Old Ones had passed on their knowledge of the original world they had nurtured, before it had been lot to them. The Elves now know only a little, only that another world exists much like their own, and that sometimes a portal may be found joining the two, at least for a time.
The lizardmen, particularly the older Slann are more knowledgeable on the subject, but few if any would dream of divulging this information to an outsider, not until 2525 that is...
Palurin was indeed nurtured and crafted by the Old Ones. The great races were settled there and carefully watched, just as in the warhammer world and civilisations of dwarfs, elves and men grew up, until a time just before the fall. Somehow the land of Palurin was lost to the Old Ones and the warp gate became inaccessible. Left to fend for themselves the civilisations of Palurin were less fortunate than those of the Warhammer world. Many fell when the great incursion of Chaos erupted through the Old Ones' ruined warp gates and by the time the Warhammer world had begun to recover, there was little left of the peoples of Palurin.
Some Elves believe Palurin was in fact the first world settled by the Old Ones. Others believe that Palurin was a second attempt at perfection, having seen their mistakes in their first. Either way another world exists, sparsely populated by a variety of races, some deliberately placed there and some an accident of fate, and this world can sometimes be reached.
The surge of magic which accompanied the fall of the Old Ones washed over both the Old Ones' creations, and between them a flux of magical energy continues to writhe and boil, creating wormholes linking the two worlds. Some are fleeting, lasting perhaps a few days never to return while others are more stable, often existing for thousands of years.
Following the Albion campaign it was a man of the Empire, Ludwig Raustaber, who came back to the Empire with tales of a wondrous world ripe for colonisation, only unlike similar stories considered the work of madmen, Raustaber brought evidence, introducing the Empire to a strange new root vegetable the like of which had never been seen.
And so in 2525 the Empire started to take the idea of a "strange new world" more seriously. Unfortunately they weren't able to keep this discovery quiet and soon fleets of Bretonnian, Estalian and even Dwarf adventurers were setting sail to the mysterious Isle of Albion. Further investigations found several quasi-static portals, some onshore and some out to see, which did indeed show a mysterious land beyond. Eventually these expeditions gathered enough courage to enter and before long several expeditions had set out and return safely.
Just as the nations of the old world were beginning to exploit this new resource, even establishing colonies in the new world, each one was visited by strange and powerful individuals. Representing the High Elves of Ulthuan and the Lizardmen of Lustria, an ancient Slann and the Loremaster of Hoeth travelled the Old World warning each government in turn to stay away from the portals.
In essence, they explained, the portals were unstable. Not only would these new ones be likely to close at any moment, the humans and dwarfs had not understood the wormholes' true nature. For now all seemed well, but no portal would remain so for long. Dangerous time dilation and warping would likely occur. A traveller might pass into the new world hundreds of years after a man who entered just before him, and then return hundreds of years later back to his old world, having stayed for just a few minutes in Palurin. Worse, it was possible for a man to cross over the magical void, and find himself returning into the past, or into a world changed through accidental changes to history.
By now however it was too late, as the Empire and Bretonnia had already sent vast contingents across to the new world to claim it for there own. Worse still, news from Albion reported that Malekith, ever eager to exploit an opportunity (and possibly lose a few troublemakers at the same time) had sent a huge host of Dark Elves through the portal.
Fear gripped the high elves. What if the Dark Elves were to return in their past and defeat their Kin? Ulthuan would be lost! With no other solution appearing viable, the King of all the Elves sent through a mighty warhost, instructing them never to return, and to make sure no one else did. In honour of their ancient alliance, the Lizardmen followed, casting a powerful spell as they did so, causing the Albion wormholes to destabilise and vanish after less than six months. In the Old World talk of the portals was suppressed, with the expeditions to the "New World" being understood as lost expeditions to Lustria, as many had actually thought was the case in the first place. The great migration was over and Albion once more treated with suspicion and dread.
Meanwhile on Palurin the new arrivals did not find the world empty. Though the ancient civilisations had long since collapsed, the world was inhabited by tribes of men, beastmen, greenskins and even Vampires. Many had been seeded there by the Old Ones, but some were later arrivals. Many man of the north had blundered into the world of Palurin over many centuries, as had roving orc and beastmen warbands, and in the deep forests of Palurin were secretive wood elves, descendents of wood elves who had found their way into Palurin through a quasi-stable gateway in Loren. In fact the wood elves had long since used this portal as a punishment (in the form of permanent banishment) for a millenia, and so a mirror kingdom of the wood dwelling elves had been established on the other side of the wormhole. The elves however knew better than to try to return.
Fortunately for the Warhammer World Palurin has far fewer portals, so that most find themselves on a one way trip to a new world, as did the expeditions of 2025. Occasionally word would come from the Old World through a new expedition, usually small, or a disoriented stranger who had wandered off in the forest, but for the most part the world of Palurin was now home to these colonists, whether they liked it or not.