Can I change beliefs and rules of an existing faith?

[AlduinTWE]

If I wanted to change certain doctrines, marriage rules, what is shunned and not etc, of an existing faith, could I? I'm playing the emperor of the Byzantine Empire and I am the liege of the head of the Orthodoxy faith.

[brownacs]

Kinda. You'll create a new religion that's part of the same religious family as your old one (if the religion's unreformed like say Asatru then you create the organised version of that religion but that's not applicable to Orthodoxy which is already organised). If you click on the religion tab which you can access either by clicking on any character's religion or by clicking the second button up on the bottom left (has your religion's symbol), there's a 'create new <whatever> faith' button. Press that. Costs more piety the more you want to change by the by so it can be a good idea to get the learning lifestyle cost reduction perk if you're wanting to make quite radical changes.

[armyissue69]

YES, you have to control at least 3 holy sites. Click on you Faith (Orthodox) at the bottom select reform faith.

To lower the costs of reformation there are several means to lower it. Culture traditions and Learning education stuff.

IF you reform the faith, there will be an OLD faith area, and a few NEW faith areas, and each of you would consider the other astray (I think). Been awhile since I reformed an already organized faith.

There are other cultures/areas of play that have holy sites closer if you wanted to do a run just for reformation experiences.

[AlduinTWE]

Thank you! :)

[PostalGibbon]

You cannot alter beliefs/tenets of faith that already exists like Catholic or Orthodox as example.

You can however reform a preexisting faith (if you are controlling 3 holy sites), choose beliefs for that faith and then start force converting your vassals and put your realm priest to convert county job.

And converting counties/peasants will take a long time depending your new faiths fervor and fervor of the old faith (Orthodox?). Single county conversion takes about 2-3 years minimum to maximum of 50 - 100 years to eternity. It is quite fast on small sized realm but gets almost impossible to convert whole realm if you have empire size realm.

And your new faith is target of holy wars even if your new faith is Christianity because you lose ecumenism.

So think twice the negatives before you change your current faith.

[Mati_Lublin]

Honestly, with legends and giving your vassals directions conversion is quite fast. Saintly legend (illustrious and better quality) gives decision to insta-convert vast swatches of your realm (50% chances each county).

[Emperor Jeff]

In addition to the above, certain faiths can be changed via event chains (basque paganism, adoptionism(?) and mozarabic, i believe)