Oh, the Hanseatic League game. I played that once. It involved an awful lot of sailing your trading cog up and down the Baltic, apparently in real time. I like games very slow, but this was too much even for my taste. If I had stuck with it I think there would have eventually been fighting to defend a city and perhaps a city-builder aspect?

Hanse: Die Expedition (1994) - https://www.mobygames.com/game/9273/hanse-die-expedition/

There's also the Patrician series (Patrician 1, 1992, Patrician III 2002) I think you may be referring to: https://www.mobygames.com/game/15367/patrician-iii/

Patrician III starts out as a manual trading game, sailing your trading cogs up and down the Baltic, but then to expand you build industries, and supply goods so the population can expand and create and consume more of your goods, automate trading routes, you can become mayor of your home town, defend it against sieges, and it to a large extent turns into a city builder.

You can also send ships to explore and find trade routes to the Mediterranean, and IIRC you can occasionally accidentally discover America.

Very cool game.