Advance
Reichsmessestädte
Imperial fairs are a rare privilege granted to only a few select cities, creating some of the largest marketplaces in Europe and making these cities the commercial heart of the Holy Roman Empire. The centralized nature of these markets allows merchants to plan and negotiate effectively in a setting where they can benefit from freedom and access to a diverse variety of goods.
GermanyFormable CountrypotentialAdvance tree
The game files don’t say where this goes: it has no requires, so the game places it in the 
Reformation tree itself.
Modifiers
Definitionin_game/common/advances/culture_group_german.txt:284
286icon = genoese_banking_traditions