Why cant Riga form Prussia?

[slovak_mercenary]

I want to play as Riga and complete the 3 achievements "Terra Mariana", "A Fine Goosestep" and "An Early Reich". The problem is, that I cant form Prussia. Is it a bug or is it normal and why?

[Tulduil Iphukiir]

How do you know you can't form Prussia?

As Riga you have to take this Decision:
https://eu4.paradoxwikis.com/Prussia#Reform_into_Prussia_2

One of its requirements is to not be a Theocracy. So change your government type to a Monarchy, convert to Protestant or Reformed, conquer Königsberg, Warmia and Danzig and have Adm Tech 10.

[tonypa]

There are 3 ways to form Prussia:
- as Brandenburg
- as Teutonic Order
- as any country with primary culture Pomeranian, Saxon or Prussian

For Riga 3rd option allows to form Prusia. Culture shift to Pomeranian, Saxon or Prussian; owns core provinces Königsberg, Warmia and Danzig and convert to Protestant or Reformed

Missed the Theocracy condition ...