The religion that a nation follows and how tolerant it is of other faiths is an important aspect of gameplay in EUIV. Religion will affect diplomatic actions and nations of mutually accepted religions have a better chance of reaching agreements with one another. Religion is also connected to unrest and provinces of non-tolerated religions are more rebellious. The player has some control over religion by having the option to change the state religion, religious decisions that may impact internal and external religious relations, and sending missionaries to convert heathen or heretic provinces to the state religion.
Religious unity is the percentage of a country's development provided by provinces that follow the state religion or a positively tolerated heretic or heathen religion, excluding any assigned to trade companies.
- Provinces of the state religion always contribute 100% unity regardless of tolerance.
- Provinces of a heretic or heathen religion contribute a percentage determined by how tolerated they are.
The effects of tolerance on religious unity per province are as follows:
For example, suppose a Catholic country has a 10 development Catholic province, a 4 development Protestant province, and a 16 development Sunni province. If heretic tolerance is +1 and heathen tolerance is -2, the country's religious unity will be (100%*10 + 50%*4 + 0%*16)/(10 + 4 + 16) = 40%
Ideas and policies which increase religious unity:
Religious unity directly affects the following:
- for each percentage point of religious unity:
- for each percentage point of religious unity below 100%:
|+1.0%||Stability cost modifier|
Countries have three tolerance values. These tolerance values are national, but have provincial effects depending on the province's religion, relative to the state religion.
Each point of positive tolerance gives:
Each point of negative tolerance gives:
Additionally, positive tolerance of heretics and heathens allows those provinces to contribute to religious unity (see above).
This refers to the state religion. For example, if the state religion is Catholic, Catholic provinces will use this tolerance value. The base value of tolerance of the true faith is +3, and there is no maximum value.
This refers to different religions within the same religious group. For example, if the state religion is Catholic, the religion group is Christian, and provinces that are Protestant, Reformed, Coptic, or Orthodox will use this tolerance value. The base value of tolerance of heretics is –2. The possible maximum value is +3.
Tolerance of heretics of ≥ 2 will allow provinces to randomly convert to those heretic religions. The median time to happen is 5000 months, lowered by Innovative Ideas and having a neighboring province with the new religion while increased by having the Theocracy government type. Provinces with the "Religious Zeal" modifier will not receive these events at all.
A province is more likely to convert via event to a particular religion if a neighboring province has that religion. Adjacency is not required for most conversions. However, the following conversions only occur if a neighboring province has the new religion:
- Orthodox ↔ other Christian
- Buddhist, Shinto → Confucian
In addition, only Japanese-culture provinces can convert to Shinto.
This refers to religions of other religious groups. For example, if the state religion group is Christian, provinces that are of Muslim, Eastern, or Pagan religious groups will use this tolerance value. The base value of tolerance of heathens is -3. The possible maximum value is +3.
Ideas and policies that affect Tolerance of heathens:
Each Christian or Muslim denomination can have one Defender of the Faith. It costs 500ducats for a country to claim the title. Countries with female rulers or regencies cannot claim the title. Being Defender of the Faith gives the following modifiers:
Countries automatically call the Defender of the Faith of their religion to arms if attacked by a nation of another religion. Since patch 1.8, it seems the Defender of the Faith gets a call to arms only for countries on the same continent or sharing their border. The Defender of the Faith doesn't get a call to arms if the country attacked is a co-belligerent (e.g., if France is the Catholic Defender of the Faith and Venice (Catholic) is allied with Serbia (Orthodox), then if Ottomans (Sunni) attack Serbia and make Venice co-belligerent, France doesn't get a call to arms).
Catholic countries that hold the Defender of the Faith title cannot be excommunicated by the Papacy, regardless of relations.
The Defender of the Faith loses the title, but no prestige, if they refuse or lose the war.
If Defender of the Faith refuses call to war, it gets a 5-years truce with the country that was calling. Therefore, if your ally is Defender of the Faith and you have a common enemy of the "defended" religion, this ally will not be able to join you in an offensive war against this enemy, as AI wouldn't break a truce.
All other countries of the same religion get a +10 “信仰守护者” relations boost with the Defender of the Faith.
The most common way to convert provinces is the use of missionaries, but there are also several other methods.
Missionaries are envoys that can convert a province to a nation's official religion. Missionaries slowly convert provinces over time: each month, the effective missionary strength in that province is added as ongoing progress, and when it reaches 100% the province is converted. If strength is insufficient, the province will never convert (although the missionary will not lose progress). An active missionary in a province will increase the unrest there by +6%.
Ideas and policies:
Decisions and events:
|+2||Counter-Reformation||Decision: “Embrace the Counter-Reformation”||until one of the four “The Counter-Reformation Ends” events.|
|+1||Melchior Klesl||Austrian event: “Melchior Klesl”
||until ruler changes.|
The player can adjust the missionary maintenance cost by a slider on the economy interface between zero and full funding. Reducing the funding reduces missionary strength linearly, up to −2% missionary strength without funding. At full funding the costs of an active missionary are 5 per year. These cost are increased by 0.5% for every year since 1444, just as advisor cost.
- 顾问： +2% 审讯官顾问
- 稳定： +0.5% 每一点正稳定
- 虔诚： +3% 穆斯林国家满虔诚（正比于虔诚值）
- 牧首权威： +2% 东正教国家满牧首权威（正比于牧首权威值）
- 科普特祝福： +1.5% 科普特派国家拥有Send Monks to Establish Monasteries祝福 (需DLC 人权)
- 建筑： +3% 大教堂
- 决议： 一系列国家决议可增加或降低传教力量
- 事件： 某些事件可影响传教力量
- 省份当前宗教： +2% 于原始宗教组省份
- 神圣罗马帝国： +1% 是神圣罗马帝国官方宗教
- 阶层： +2% 教士阶层忠诚大于60%时教士阶层封地
- 通过宗教界面转教将给予十年"宗教狂热"修正， 对异端传教力量+10% ，对异教无效
- 省份当前宗教： -2% 于科普特、穆斯林和神道教省份。
- 省份当前宗教： -1% 于东正教、锡克教省份。
- 文化： -2% 于文化未接受的省份。
- 贸易公司 所属省份 -100%
- 省份发展度： 没一点省份发展度 -0.1%。
- 宗教中心： 于罗马、麦加、锡克教发源地及所有新教、改革宗的改革中心 -5%。
- 新近转教的省份 -100%，表现为持续30年的"宗教狂热"修正。
The first three nations to convert to Protestant and the first three to convert to Reformed, in Europe, have a random province designated as a Center of Reformation. These centers of reformation will automatically convert nearby provinces to their religion, unless they are conquered and converted to a different faith. Provinces converted by a center of reformation get the -100% religious zeal modifier to missionary strength in that province for 30 years. Missionaries can't work in the same province that is being converted by a center of reformation. Each center of reformation can only convert one province at a time.
There are several different ways a country may change religion.
Catholic, Protestant and Reformed Christians can convert among each other through the Religions tab once the Reformation starts. Hindu and Sikhs may similarly interconvert once Sikhism is unlocked.
Conversion is also possible through decision: with the Sword and Crescent DLC, Sunni and Shiite (but not Ibadi) Muslims may convert to the other denomination if both their capital and the majority of their provinces follow the other denomination. Japanese daimyos - but not Japan itself - may convert to Catholicism by decision if the majority of their territories are Catholic; this can happen following certain events in the 16th century.
Countries of other religions cannot convert peacefully, but can change religion due to warfare or rebels.
Totemist and Animist pagans get events to convert to Catholic, Protesant or Reformed Christianity if they have neighbors of the appropriate denomination and a sufficient positive opinion with that neighbor. Kongo and Ming have special event chains to convert to Catholicism. Some nations for example Sweden has unique events where it is possible to change religion.
A nation can force a heretic (but not a heathen) country to change their state religion as part of a peace deal. Without an appropriate casus belli such as "Cleansing of Heresy" or "Religious Conformance" (unique to the Holy Roman Emperor against HRE members), this will have the same war score cost as annexing the nation. When a country is converted this way, only the state religion and the capital province's religion change.
Once the religion of the Holy Roman Empire has been locked, the emperor can request a prince to change their state religion depending on their opinion of the Emperor. Similarly to when forcing a religion of an enemy country, the prince has its capital converted while the rest of the provinces remained unaffected.
With the Common Sense DLC, suzerains may force their subject nations to change religions if they follow a different faith. If heretic, this gives +50 liberty desire, and if heathen +100 liberty desire, both gradually ticking down.
Nations can support religious zealots in enemy countries. These rebels convert a province's religion to the one they represent when occupation is achieved.
Supporting religious zealots is only possible if the desired religion is present in the target nation and is the likely rebel type in a province with unrest above 0. If there are no such provinces in the target nation, one way to achieve it is to sell the target a province of the correct religion.
Generally the nation will be able to overpower the rebels if left to its own devices, so it is critical to support them militarily. This can be done by declaring war against the target nation using the "Support Rebels" casus belli.
A nation that is broken by religious rebels, or that accepts their demands, will convert to the rebels' religion provided that the rebels' religion is the plurality religion. For most countries, giving in to religious rebels is the only way to change religious group.
However, even rebel conversion won't convert you to a Pagan religion group faith unless you already belong to that religion group.
- Base missionary strength is very small compared to modifiers, both positive and negative. This means that conversion will usually either be very fast or impossible. Religious ideas is often essential for any serious conversion work.
- Provinces that do not have the state religion generally suffer from low tolerance and also lower the nation's Religious Unity. Therefore, nations with large amounts of wrong religion provinces will have to choose between two main ways of dealing with them- high tolerance or conversion. They are represented by the Humanist and Religious idea groups respectively.
- See in Static modifiers#Religious unity). (
- See in Static modifiers#Inverse religious unity). (
- See in Static_modifiers#Tolerance). (
- See in Static modifiers#Intolerance). (
- See in Static_modifiers#Active missionary). (
- See in : MISSIONARY_MAINTENANCE_FACTOR = 5,
- See in : ADVISOR_COST_INCREASE_PER_YEAR = 0.005, -- yearly increase in price in percent,
- See patch 1.12.