Troth Glenbeard was a dwarf with a mission. And that was destruction.
From there, things happened. And the Irondeeps got a Subterranean-Transport-System-That-Moves-Things-Around-Faster-Than-Equine-Means (aka, in modern-speak, a subway).
Alchemical Gold - popular in the weapons of the nobility, this allows for gold to be used in their swords and lances without the fear of the metal bending, deforming or otherwise breaking in combat.