from the Mystara Mailing List posted 22 September 2005.
When Mealiden's migration arrived in the lands south of the Nithian Empire. They were attacked by the Nithians, and were soon driven west passing through the grasslands of Kerendas, they were fascinated with the wonderful wild horses that roamed the land, and befriended them. Elves do not domesticate animals as the humans had begun doing, but some horses were brought along as the elves travelled into the Forests of Traladara. As the Callarii remained there their fascination with horses grew. This was encouraged by their Clanmaster, Lady Callarii. She seemed relieved of some of the sorrow she felt when she was around horses. As the centuries passed, the Callarii became master horsemen and their horses were admired by all others.
Centaurs had also moved into Karameikos. They came from the great Ethengar Grasslands in the north, and also offered advice on how to raise the best horses.
But one day the Centaurs approached the elves with a problem. A strange Plague raged the land. (The Lycantrophic Plague of 425 AC -Ed.) It mostly affected humans, causing them to take the form of predator animals and turn to evil ways. Some said the days of the Beastmen had returned. Others believed it was an ancient Taymoran Curse that had been brought upon them. The elves seemed unaffected by this Plague. Some Centaurs, however had been affected. The elves brought the Centaurs to their Treekeeper, who was after a while able to find a cure. However, it was not a complete cure. The Centaurs who had been cured were no longer affected by the madness associated with the disease, but were still able to change their shape between Centaur and Horse form. Thus the Chevalls were born. These became Sages and Shamans of their Tribes.
To thank the elves, the Chevalls, who were given an even deeper understanding of horses, due to their shapeshifting abilities, had a proposition. With the aid of Unicorns, they could create a new kind of horse for the elves. These horses, magical creatures in their own right, became known as elven horses, and were superior to even the best ordinary horses. The elves felt that the elven horses were the symbol of eternal friendship between them and the Centaurs and Chevalls and agreed that only elves would be allowed to ride these magnificent beasts. However Lady Callarii, still the Clanmaster now, 400 years later ordered that some of these horses should be taken to Alfheim as a gift to their allies and friends in that new Forest Kingdom in the north.