This article may contain outdated information that is inaccurate for the current version of the game. It was last updated for 1.10.
- For information on individual religions, see religions and denominations. For religious events, see religious historical events.
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.
- 1 Religion map
- 2 Religious unity
- 3 Tolerance
- 4 Defender of the Faith
- 5 Conversion
- 6 Strategy
Religious unity is the percentage of a country's tax base provided by provinces that follow the state religion or a positively tolerated heretic or heathen religion.
- 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:
Religious unity directly affects national unrest and stability cost as follows:
- National unrest: +0.02 for each percentage of religious unity below 100%
- Stability cost: +1% for each percentage of religious unity below 100%
Ideas and policies which increase religious unity:
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:
Tolerance of the true faith
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.
Tolerance of heretics
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.
Heretic conversion events
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
- Buddhism, Shinto -> Confucianism
In addition, only Japanese-culture provinces can convert to Shinto.
Tolerance of heathens
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:
Defender of the Faith
- +5% Morale of armies
- +5% Morale of navies
- +5% Technology cost
- −0.025 Monthly war exhaustion
- +1 Yearly papal influence
- +1 Yearly prestige
- +1 Missionary
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 Defender of the Faith get a call to arms only for same continents countries and for countries which has a border. The Defender of the Faith doesn't get a call to arms if the country attacked is co-belligerent (i.e. France is Defender of the Faith of Catholics, Venice (Catholic) is allied with Serbia (Orthodox); if Ottomans (Sunni) attack Serbia and make Venice co-belligerent, France doesn't get a call to arms).
The Defender of the Faith loses the title, but no prestige, if they refuse or lose the war.
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). There is a 0.42 gold/month cost per active missionary, and a province being converted will have +6% local unrest.
Each country has 1 missionary by default. More can be obtained through the following:
- +1 missionary from being Defender of the Faith (Christian or Muslim only)
- The following triggered modifiers award more missionaries:
- +1 missionary from being Christian and owning Mecca.
- +1 missionary from being Christian or Muslim and owning Judea/Jerusalem.
- +1 missionary from being non-Catholic and owning Rome.
- +1 missionary from being Orthodox and owning and converting Rome, Constantinople, Aleppo, Judea/Jerusalem, and Alexandria.
- +2 missionaries from joining the Counter-Reformation (Catholics only)
Base missionary strength is 2% at full funding, scaling down to 0% at no funding. Modifiers that increase strength include:
- Advisors: +2% from an Inquisitor advisor
- Stability: +0.5% for each point of positive stability
- Piety: Up to +3% for Muslim states that are pious
- Patriarch Authority: Up to +2% for Orthodox states that have Patriarch Authority.
- Buildings: +0.1% for each fort level in a province, +3% for a Cathedral
- Decisions: A number of national decisions increase (or decrease) missionary strength.
- Events: Many events give a temporary bonus (or penalty) to missionary strength.
- Province's current religion: +2% in pagan provinces.
- Holy Roman Empire: +1% for being the dominant religion in the Holy Roman Empire
- Converting religions through the Religion tab gives a +10% "Religious Zeal" bonus for ten years, but only to converting heretics, not heathens.
- Several ideas also affect missionary strength:
In addition, a few ideas specifically affect missionary strength when converting heretics, but have no effect when converting heathens.
|—||—||—||Religious-Offensive: The Anti-Heresy Act|
|—||Religious idea 7: Inquisition
Bulgarian idea 2: Root Out the Heresies
|Kievan traditions||Welsh idea 7: Welsh Church||—||—|
Things that decrease this speed include:
- Province's current religion: -2% in Coptic, Muslim and Shinto provinces.
- Province's current religion: -1% in Orthodox and Sikh provinces.
- Culture: -2% for non-accepted cultures.
- Provincial tax income: -0.5% for each point of a province's base tax.
- Rome, Mecca and the initial Sikh province (historically Punjab, but in-game potentially any Indian province) get a special -5% Religious Center modifier.
Centers of reformation
The first three nations to convert to Protestant and the first three to convert to Reformed 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 -8% religious zeal modifier to missionary strength in that province for nearly 25 years. Missionaries can 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.
A nation can force a heretic 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.
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 from the same religious group, or that accepts their demands, will convert to the rebels' religion provided that the rebels' religion is the majority religion. For most countries, giving in to religious rebels is the only way to change religious 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. There are represented by the Humanist and Religious idea groups respectively.