“ 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.”
“ Surnames: The Chinese were among the very first cultures to adopt the use of hereditary surnames (around 2800 BC). But the custom didn't quite catch on in Europe - at least not until the Venetian aristocracy made it popular sometime between the 10th and 11th centuries AD. What culture made it popular in your setting and why?”