Expanding your territory in Anno 117 means huge expenses. Here’s what to do immediately after founding a city

Each island can only support one city. To start a new city, sail one of your ships to an empty island and land on its shore. You’ll then be able to build a trading post, but it’s expensive – you’ll need several thousand denars. Building the trading post claims the island for you, and you’ll need to pay taxes to the emperor to keep it. The trading post is the main building in your new city until you construct a villa.