Grand Ages: Medieval
50 Achievements
GOG
Cosmopolitan City
Out of all your competitors, you had the largest town or city upon reaching the rank of "Emperor".
8.3%
How to unlock the Cosmopolitan City achievement in Grand Ages: Medieval - Definitive Guide
NemoG
When you press the 
button, you can see who has the most businesses in the current game so make sure you're at the top by the time you're King. The trophy will pop when you hit Emperor. This should should be combined with Producer, Multinational and/or Megacity.