Revolution
After years under the yoke of the dragons, the people of Allheim banded together against their winged overlords, with the assitance from the Bronze Dragonflight of the Dragonplane.
It took a hundred years, but finally, the people of Allheim were ready to rise up against the Dragons. Man, Elf, and Dwarf each took up arms, alongside the Blue and Green Dragonflights, to fight against the combined forces of the Black and White dragons.
It culminated in the Battle of Breaker's Keep on the western coast of the Eastern Continent, where Lief Sigvaldson stood toe-to-toe with Var'Rysh, eventually defeating him in one-to one combat.
The White dragons retreated north, the Green dragons disappeared, the Blue dragons swore fealty to the Elves of Lor'Thal, and the Red and Black dragons were wiped out.