Religion

Founding

• The first civilization to complete a faith's technology founds it. One of that civilization's cities, chosen at random, becomes its holy city, and no one else can ever found that faith.
• Buddhism: founded by Reincarnation
• Christianity: founded by State Religion
• Confucianism: founded by Justice System
• Hinduism: founded by Polytheism
• Islam: founded by Righteous Law
• Judaism: founded by Monotheism
• Taoism: founded by Philosophy

Spreading

• Every few turns each faith has a chance to reach a city that lacks it, from the nearest city that has it. The base chance is 1.5% a turn, less 0.1% for every tile between the two cities, and nothing at all beyond 100 tiles.
• The chance is x3 when the two cities are joined by a working road.
• A city with no faith at all is x2 as receptive; a city that already holds faiths is x0.25 as receptive for each one it holds.
• Missionaries spread a faith deliberately: order one into any city that lacks the faith, yours or a neighbour's you can reach, and it converts the city and is consumed.
• Auto Spread hands a missionary to a standing order: Own Cities converts only your own cities; Own Cities, Then Abroad fills every city of yours it can reach before it goes abroad.
• An AI leader can be asked, from the Treaties tab of an audience, to adopt your state religion once one of its cities follows it. A friend may agree; an agnostic one needs only to be on speaking terms. You can also demand it: a leader gives in only when you outgun it (a founder holding its own holy city, by far more), resents being made to (-6), and resents a demand it refuses too (-3). A leader who adopts your faith keeps it 30 turns.

A missionary can only be trained in a city that holds its faith:

• Buddhism: Buddist Missionary (needs a Buddhist Monastary in the city)
• Christianity: Christian Missionary (needs a Christian Monastary in the city)
• Confucianism: Confucian Missionary (needs a Confucian Monastary in the city)
• Hinduism: Hindu Missionary (needs a Hindu Monastary in the city)
• Islam: Islamic Missionary (needs a Islamic Monastary in the city)
• Judaism: Jewish Missionary (needs a Jewish Monastary in the city)
• Taoism: Taoist Missionary (needs a Taoist Monastary in the city)

State religion

• From the government panel you may adopt any faith present in one of your cities as your state religion. It costs 100 (more in later ages); the founder of a faith adopts it for free.
• Every city of yours that holds your state religion gains 5.
• If you founded the faith, its holy city earns 2 for every city in the world that holds it, other civilizations' cities included, and 1 for every one of those cities that belongs to another civilization. Spreading your faith abroad pays twice.
• Leaders who share your state religion think better of you (+10), and a leader who has taken up a faith you founded holds +14 for you as its founder; those following another founded faith think worse (-14). See Diplomacy.

Religious buildings

Each faith has its own versions of the religious buildings, which can only be built in a city the faith has reached:

• Buddhism: Buddhist Cathedral, Buddhist Monastary, Buddhist Temple
• Christianity: Christian Cathedral, Christian Monastary, Christian Temple
• Confucianism: Confucian Cathedral, Confucian Monastary, Confucian Temple
• Hinduism: Hindu Cathedral, Hindu Monastary, Hindu Temple
• Islam: Islamic Cathedral, Islamic Monastary, Islamic Temple
• Judaism: Jewish Cathedral, Jewish Monastary, Jewish Temple
• Taoism: Taoist Cathedral, Taoist Monastary, Taoist Temple