The video hopefully shows a little more clearly the steps below.
1) Start a new game, pick any start location except where you actually want to have your Republic.
2) Pick your preferred starting county (must be coastal with a city) and bring up the mayor's profile. Note that if you don't like his starting traits you can reload a new game as these are randomly generated each time. You can also just use console commands to fix his traits and skills.
3) Open the console (~ key by default) and type "charinfo 1".
4) Hover your mouse pointer over the mayor's portrait and note his character number.
5) Type "give_title c_<county name> <character number>".
6) Type "give_title d_<dutchy name> <character number>".
7) Type "play <character number>
You are now good to go.
Alternative method that allows you to play your created ruler:
1) Start a new game, pick any start location as country where you want your Republic.
2) Open the console (~ key by default) and type "charinfo 1".
3) Hover your mouse pointer over yourself, so as to not forget how to find you. Alternative way - use "Find Character" later.
4) Hover your mouse pointer over country's ruler portrait and note his character number.
5) Type "play <character number of ruler>".
6) Type "give_title c_<county name> <character number of ruler>".
7) Invite your character to court, as he might get misplaced when you take away his county. Add cash if needed for gift.
8) Revoke mayor title from city mayor. WIll take up to 2 weeks.
9) Give out a landed title - city - to your character. He will become mayor.
5) Type "give_title c_<county name> <character number of your character>".
8) Type "give_title d_<dutchy name> <character number of your character>".
7) Type "play <character number>
And you can get a norse merchant republic with a strong-genius-lunatic ruler aged 16.
Testing shows there is a game-breaking bug, as the character counts holdings in province that is capital, instead of trade posts, which results in incorrect trade post counting and you are unable to construct more trade posts. Possible workaround to found merchant republic in a 1-2 holding province.
Making a Republic Without CheatsEdit
This is slightly different from above and is more restrictive but still quite possible. First of all, this can really only be achieved by kingdom/empire status rulers. This is because a mayor holding a county cannot be played by the player.
- Begin playing a kingdom/empire ruler.
- While holding your primary title, make sure that you own a county and duchy. (Doens't need to be related but can be useful)
- Make sure that your county contains a city.
- Give the county title to the mayor.
- Give duchy title to the Prince-Mayor
- Reload as Mayor now republic.
Disadvantages of this system can be that the culture/religion of the mayor will affect all families of the republic. Another problem is that areas that don't include kingdoms will require said kingdom to be created (or the county/duchy in question become owned by another ruler). The republic will become a vassal of the republic's creater and this may cause bad relations between ruler and yourself since you are two different government types (-30). This can be avoided by granting the republic independence while still being king.
Things to NoteEdit
Note that you will not start with any courtiers by doing things this way, nor will you start with any trade posts. You will however start with a larger than normal gold balance which you can use to make your own posts (though you must play through a couple days of game to have your trade post limit refreshed).
To add courtiers do the following:
1) Use the character finder to find unlanded males of your culture and religion.
2) Find their character number as above.
3) Type "move <character number>".
If your county has no 'blocks' in the Trade Practices technology then your trade post limit will remain at 0 and you will have to wait (likely take a few years) until you can raise it enough to get rid of the 100% trade post reduction limit before you can actually make a trade post. This well make for a slower start but is not unsurmountable. However you can type in "<techpoints>" cheats to improve your Trade Practices tech.
If your ruler is not as good as expected you can use the Ruler Designer DLC. To give him the necessary traits to make him an efficient Doge.
Enjoy your new republic.