Build spy network on pomerania.ĩ0% of the time Bohemia will rival you, in which case rival them back. In my experience, if you set your rivals early, they tend to seek stronger allies which will slow down your conquests. And you are in the HRE, so expansion can get rather slow because of aggressive expansion and demand for unlawful territory by the emperor. Brandenburg starts fairly weak in close proximity to some bigger nations such as Bohemia, Poland and Denmark. And Prussia is a very strong nation with one of the best militaristic national ideas. The main reason is that forming Prussia from Brandenburg is a natural progression in game.
Although a fairly small nation, it’s widely popular with EU4 players. Brandenburg starts with 6 provinces in the HRE with only 57 development.