Expedition to the Razor Cliff
No one is sure what happened to the Empire, but at the zenith of it’s rule, it covered most of the landmass of the continent. This lead to great cultural development, the codification of magical experiments into magical training and mandatory schooling for those gifted with the ability to work magic. The churches of the major religions banded together to support the nobility and provided a strong counterpoint to the military and wizardry classes that developed.
Traders could be found bringing wares from one side of the continent to the other, and a variety of human cultures mixed and mingled, leading to very few problems related to skin colour.
The dwarves of the north and west had allied themselves with the Empire early, and helped develop the military equipment and tactics that allowed the empire to expand. The nomads of the plains helped develop cavalry and tactics after they were conquered through magic.
The elves fought the empire to a stand still in a long war that left elves discriminated against in the cities after suing for Ally status.
Halflings were conquered quickly and early in the growth of the Empire and were made slaves. Most nobles will have at least halfling chef, and one or two other house slaves of this race. In the countryside, this has left most folks leery of halflings, wondering if they’re escaped or freed slaves.