- Catholicism: the Pope
- Orthodox Christianity: the Ecumenical Patriarch
- Miaphysite Christianity: the Coptic Pope
- Sunni Islam: the Sunni Caliph
- Shia Islam: the Shia Caliph
Unreformed Pagans have no religious head, although they can create one by reforming the religion, called the High Priest or (for Norse) Fylkir. Some heresies also have heads, not all of which exist at game start but can be created by decision. Some religious head titles cannot be destroyed, but are always held by some character; for some heresies, frequently the only character of that religion is its head.
In most religions the religious head is part of the clergy. In Islam and reformed Norse paganism he is a noble who often wields considerable secular power. Religious heads may grant divorces, call Crusades, jihads and great holy wars (except Orthodox and Miaphysite and their heresies), and sanction invasions. The Christian religious heads can also excommunicate members of their church.
There is also a separate but related concept of a character's religious head, which is not always the same as the religion's head. This is particularly important for Orthodox and Miaphysite Christianity, which have autocephalous patriarchs; they have limited power compared to other heads. It is also relevant for Catholicism when antipopes exist.
The Pope is the head of the Catholic Church. His title has the rank of king, so he cannot be vassalised except by an emperor. The Sons of Abraham expansion added a number of unique features to the Papacy.
Main article: Papal succession
The Pope is elected by the College of Cardinals. In-game, there are nine cardinals at a time, and when the Pope dies, the cardinals elect one among their number to replace him. Vacant cardinal positions are awarded to bishops based on their total suitability score. This is calculated based on the age, traits, culture, and secular power (rank and number of titles held) of the candidate, as well as the Pope's opinion of the bishop's liege. Rulers may invest in a campaign fund to increase the chance that their candidate will be chosen.
The cardinals choose the next Pope based on a similar ranking system, which rulers cannot directly influence. However, Popes who received votes from cardinals from a particular ruler's realm will have a massive +100 relations modifier per vote received.
Catholic leaders in good standing with the Pope can call upon him for special favours. Most of these require the Sons of Abraham DLC; the exceptions are divorce, excommunication and invasion. You can ask the same things of an antipope. The piety cost is halved for realms under Papal Investiture law.
|Ask to nominate bishop||0||480 months||If under the Papal Investiture crown law|
|Ask for divorce||100 piety||-10||480 months||Spouse's family unhappy.|
|Ask for claim on duchy||100 piety||-15||480 months||By selecting "claim" when viewing the title screen for a duchy. This will only be granted if the Pope dislikes the current ruler of the duchy.|
|Ask for excommunication||100 piety||-25||480 months||Pope must dislike ruler. The target must control fewer cardinals than you do and have the same religious head as you. Moral authority > 40%|
|Ask to lift excommunication||50 piety||-25||480 months|
|Ask for money||100 piety||-50||480 months||Gives double ruler's annual income. Antipopes and vassal popes generally won't have much money to give.|
|Ask for invasion||-100||480 months||Pope must dislike ruler. Invasion casus belli. Moral authority > 50%|
|Ask for crusade||-200||480 months||Moral authority > 5%|
Main article: Antipope
Antipopes are a special feature of Catholicism. They are bishops controlled by a ruler, and hold a rival claim to the papacy.
If the Sons of Abraham DLC is active and Rome is held by a Fraticelli ruler, that ruler can, by decision, create the Fraticelli Papacy for a cost of 1000 piety. The Fraticelli religion works just like Catholicism, except that the Fraticelli Pope is duke-tier instead of king-tier.
Main article: Autocephaly
Some religions have a feature called autocephaly with intermediate religious heads called Patriarchs, autonomous in their jurisdiction, but reporting to an overall head.
The following religions use autocephaly and have the associated overall religious head:
- Orthodox: The Ecumenical Patriarch
- Miaphysite: The Coptic Pope (Miaphysite Papacy)
- Monophysite: The Monophysite Pope
- Nestorian: The Patriarch of the East
- Monothelite: The Monothelite Patriarch
- Iconoclast: The Iconoclast Patriarch
- Paulican: The Paulican Patriarch
These always exist, except that no one holds the Iconoclast Patriarchate initially; if you have the Sons of Abraham DLC, the Iconoclast Patriarch can be created decision by the liege of the Patriarch of Constantinople if both are Iconoclast. The Ecumenical Patriarchate is king-tier, and is usually the Byzantine Emperor's vassal and religious head (so he cannot appoint an autocephalous patriarch, but he has all the benefits of one); the rest are duke-tier.
Bogomilism, though a heresy of Orthodoxy, has no head.
Mending the Great Schism
If all five seats of the pentarchy; Constantinople, Rome, Jerusalem, Alexandria, and Antioch; are controlled by Orthodox bishops whom are all, along with the religious head, vassals (direct or indirect) of an independent ruler of the same religion, this liege has a decision to mend the Great Schism. This gives all Catholic characters the opportunity to convert to Orthodoxy and makes Catholicism and its heresies into heresies of Orthodoxy. This will not happen to Miaphytism or Nestorianism, however, likely because these branches of Christianity broke off before the Great Schism.
Iconoclasts, Paulicians, and Monothelites can also mend the schism if one of these heresies manages to replace Orthodoxy as the parent religion. Bogomilists, having no religious head, cannot mend the schism. Miaphysites, Nestorians, and their heresies, though they use the same mechanics as Orthodoxy, cannot mend the schism either.
Recreating the caliphate
While the papacy and patriarchate always exist, the caliphates function as regular titular feudal titles and are destroyed if their holder becomes unlanded. However, it is possible for a Muslim ruler to recreate the caliphate. The title may be created through the regular Create Title interface, but has special requirements:
- Shia, Sunni, Ibadi or Hurufi (as appropriate)
- 1000 Piety OR Sayyid trait (male-line relative of Mohammed) OR Mirza trait (son of a Sayyid mother)
- (1000 Piety AND Sayyid trait) OR (control Mecca AND control Medina) OR (control Baghdad AND control Damascus AND control Jerusalem).
Getting the Sayyid trait into a dynasty requires matrilineally marrying non-Muslim men with the trait, since Muslims cannot marry matrilineally.
The Yazidi heresy also has a head, though it is called a "sheikhdom" and does not need holy sites or traits to be created, only the appropriate religion, 1000 piety, and its de jure capital county, Mosul.
With The Old Gods DLC, Zoroastrians can restore their ancient religion to prominence by retaking the Persian Empire and appointing a Moabadan-Moabad (Priest of Priests) who will function thereafter as a religious head. A notable feature of the Moabadan-Moabad is his ability to call Great Holy Wars without having to wait until the 11th or 12th century like Christians, Muslims or Reformed Pagans.
Reforming Pagan Religions
It is also possible in The Old Gods to reform Pagan religions. This has the following effects:
- The old, unreformed religion has "old" in front of it, showing that it's the unreformed version. e.g. "Old Tengri".
- The religion becomes organised, getting a permanent +20% moral authority, which makes conversion of others easier and makes them less prone to conversion to other religions.
- The religion gets a head. This is a duke-tier vassal like an Orthodox Patriarch, except the Norse Fylkir who is a secular ruler like the Muslim Caliphs. The leader can call crusades (usually under the name "Great Holy War").
- Rulers gain access to the Holy War casus belli.
- Rulers lose access to the Subjugation casus belli.
- Religions that get a defensive attrition bonus (all but Tengri and Aztec) lose it, but holdings keep their levy/garrison size and strength bonuses.
- Rulers may set Crown Authority higher than Low.
- Rulers may use succession laws other than gavelkind (and ultimogeniture for Mongols).
- Independence wars no longer have increased ticking warscore, making them harder to win.
- The "short reign" opinion penalty returns to its normal level (50% higher than other religions when unreformed).
- For Norse and Tengri, rulers lose the prestige penalties for being at peace, but gain the usual opinion penalties for raising troops.
It is possible to reform any of the Pagan religions except the generic Pagan and Hellenic religions. This requires either all five holy sites, or three holy sites, 50% moral authority, and 750 piety.
A Jew who restores the Kingdom of Israel can, by decision, reinstate the office of Kohen Gadol, or High Priest. Like the Zoroastrian religious leader, the Kohen Gadol can call Great Holy Wars as soon as his office is reinstated.