A royal marriage is a weak diplomatic agreement that can be reached between countries of compatible religions.
Making Royal Marriages
|Religion||Other compatible religions|
|Sunni||Hindu, Buddhist, Confucian|
|Shiite||Hindu, Buddhist, Confucian|
|Hindu||Sunni, Shiite, Buddhist, Confucian|
|Confucian||Sunni, Shiite, Buddhist, Hindu|
|Buddhist||Sunni, Shiite, Hindu, Confucian|
|Orthodox||Catholic/CrC, Protestant, Reformed|
Making a royal marriage is a diplomatic action. Making royal marriages is not allowed when you are at war with a country, and the two countries must have compatible state religions. A pair of countries can always make a royal marriage if they have the same religion. Some pairings of different religions are also allowed; see the table on the right. After the Edict of Tolerance (circa 1650), the restrictions on royal marriages between various kinds of Christians are lifted, and all Christians can make royal marriages with each other.
A royal marriage proposal will almost alway succeed if relations are from -149 to -6, or from +26 to +200. (Rare exceptions are observed; more research is needed. Perhaps badboy affects it?) Occasionally royal marriage proposals may succeed in the range -5 to +25, although this is quite rare.
Immediately upon a successful royal marriage, relations between the two countries are raised by 15 points. If a request for a marriage is rejected, relations drop by 5 points. Either way, one diplomat is expended.
There a few special cases. Other countries cannot make a royal marriage with the Papal States or the Knights: they can ask, but this will only degrade relations and expend a diplomat. The Papal States and the Knights can have royal marriages only if they initiate them. Two countries (France and England) have "spymaster" scripted events that, when choosing the right option will lead to a number of royal marriages with neighbors, even if those royal marriages should not otherwise be allowed because of incompatible state religions.
Effects of Royal Marriage
When a royal marriage exists between two countries, the following effects apply:
- "Fog of War" is lifted between them. Both countries can see what the other sees.
- Diplomatic vassalization is possible (along with other factors). Diplomatic annexation requires religions compatible of royal marriage, but not a marriage itself.
- Relations between the two countries are not degraded by casus belli existing between them.
- Each country may claim the throne of the other. AIs never claim thrones.
Royal marriages last for 25 years. You can see how long a marriage has to go by mousing over it on the diplomacy screen to get the tooltip.
Breaking Royal Marriages
A royal marriage may be broken at any time, as a diplomatic action. Unlike all other diplomatic actions, for some reason breaking a royal marriage costs 2 diplomats, not just 1. It causes a 1 point loss of stability on the country breaking it, but there are no other ill effects. In particular, relations are not decreased, which one might expect. Small countries can sometime exploit RMs to raise relations cheaply with other countries: see making and breaking royal marriages.
Countries sharing a royal marriage generally cannot be at war with each other, but the marriage does not prevent war. Instead, whenever a country enters a state of war against a second country with which it has a royal marriage, the royal marriage is automatically broken. The stabhit is taken by the country making the declaration of war, if the royal marriage was with the target country. Otherwise, it is taken by the country joining a war last, usually the player's country since AIs always get to join first.