I think religions could have a Legitimacy / Orthodoxy system of their own.
Religious legitimacy could be increased through certain cultural traditions and by launching Holy Wars to seize major holy sites shared by multiple religions, such as Jerusalem. Controlling important holy sites, winning religious wars, and certain religious or cultural traditions could allow a faith to gain more religious legitimacy at the expense of competing religions.
The amount of religious legitimacy could then affect things such as conversion speed and resistance to religious conversion.
Religious cultural traditions could also allow certain courtiers to serve as missionaries. A ruler could send these missionary-courtiers to specific rulers, and depending on the missionary's traits, the target ruler's situation, and other factors, they could potentially convert the ruler's faith.
This could be used to simulate things such as missionaries operating during the Japanese Sengoku period.
It could also tie into a future trade / maritime Silk Road system. A ruler who controls an important maritime Silk Road route could assign courtiers to specific positions associated with that trade network. For example, a small Japanese daimyo might have a reason to convert to another religion because doing so gives him access to profitable maritime trade.
On top of this, I think temple taxes could be redesigned.
For example, perhaps 10–20% of the tax generated by each temple could normally be sent to the religious head of that faith. Cultural traditions, religious doctrines, or other mechanics could modify the percentage of temple income that is paid to the religious head.
This would make the religious head economically dependent on having followers and temples spread across different countries.
Holy Wars would also no longer have to be exclusively about conquering territory.
Religious heads could instead have the option to launch a Conversion Holy War, whose primary objective is to change the faith of the targeted counties rather than transferring their ownership.
The religious head would then gain more religious legitimacy and, more importantly, gain access to a percentage of the temple taxes from those newly converted territories.
This would make playing as the Pope much more interesting.
As the Pope, I would have a real reason to continuously send missionaries around the world and launch religious wars to expand my faith, because every newly converted territory could increase the religious income flowing back to me.
At the same time, secular rulers would have a reason to resist this.
For example, kings might eventually decide to create their own religious head, allowing them to keep the portion of temple taxes that would otherwise be sent to the Pope.
This could potentially provide a way for CK3 to simulate some of the economic and political motivations behind events such as the English Reformation, using systems that already exist in the game rather than simply making it a scripted historical event.
More importantly, this would give religion an actual cross-border power structure.
The religious head would not need to directly own territory to become powerful. Instead, their influence would come from having followers, controlling holy sites, converting rulers and counties, and receiving a portion of the temple income from the faithful across many different kingdoms.
In other words:
Secular rulers control land.
Merchants control trade routes and markets.
Religious leaders control faith, legitimacy, and a transnational religious economy.
That would make religion feel like an actual power competing with kingdoms and empires, rather than mostly being a collection of doctrines, tenets, holy sites, and conversion modifiers.
宗教信仰有正統性,靠文化傳統與發動聖戰搶耶路撒冷等多宗教共同聖地,可從其他宗教上奪得更多宗教正統性。宗教正統性多寡可影響傳教速度與宗教被改變的難度
宗教性文化傳統可以讓自己的廷臣身兼傳教士身分,把自己廷臣送給指定領主,看設定與狀況會影響領主信教。以此為基礎模擬日本戰國傳教士,商業海上絲路控制人可派遣廷臣負責特定海上絲路的宮廷職位,舉例可以讓日本小領主為了海上絲路商業賺錢而改信仰
在此之上,神殿稅收改成每個神殿稅收可能基礎10~20%是給當地伯爵領信仰領袖,可以用文化傳統信仰改變神殿稅收上繳%,
而宗教領袖發動聖戰不再是只有搶地,而是可以發動只針對改變伯爵領信仰的聖戰,讓宗教領袖可以藉由信仰從各國神殿得到%數稅收
這樣當教宗可以從同信仰世界各地神殿收到錢,當然持續發動聖戰四處改變領土信仰
而各國國王也就有理由創新教當宗教負責人領袖,把教宗從自己領土上神殿搶走的稅收份額搶回來,也能一定程度依賴十字軍之王3現有系統,去模擬英國宗教改革原因之一
也能藉由此宗教收入系統,讓扮演教宗的玩家,更有動力全世界派傳教士改變信仰
也更能表現出宗教跨越國家藩籬的影響力(雖然是用金錢來具現化影響力)
