There are two large issues with legitimacy in the unmodded game:
Legitimacy is so readily available as to never cause a concern. The most obvious way to gain it is by setting up royal marriages, which cost but a diplomat and grant +0.5 legitimacy a year. There's no risk associated with marrying vassals daughters, if we ignore the risk of bearing ugly children. Personal unions won't derive from marriages with vassals, that is. Maximum war exhaustion (around 20) determines a loss of 6 legitimacy per year — it's not impossible, nor hard, to conclude twelve royal marriages.
The latest beta changes to attrition further increase legitimacy — less attrition leads to less war exhaustion and thus more legitimacy. Regencies remain a temporary threat to legitimacy (4), but having established that war exhaustion is easily offset with royal marriages, it's easily demonstrated that the "Royal Palace", prestige, trading in Chinaware and Grand Marshal all can void the 15 years or so of regency.
This first point deserves an observation: I've never seen a player use up cultural tradition to hire a "Grand Marshal".
This is what maximum legitimacy entails in vanilla, the values are reversed when legitimacy is zero:
The many decreases to revolt risk, in vanilla, were discussed elsewhere
. It suffices to note that maximum legitimacy results in -4 revolt risk (-4.25 in provinces where tolerance is negative). Tolerance (+1) increases population growth, diplomatic relations, tax income, decreases stability cost (mod) and revolt risk. Since legitimacy will inevitably remain high all these positive modifiers set monarchies apart from republics
To balance the dynamics revolving around legitimacy it was decided to keep the positive effects it bestows, with but a few tweaks, but increase the sources of concern according to circumstances (regencies, dynastic change, espionage, offensive war lost, high war exhaustion). Over the entire grand campaign one should expect his legitimacy to drop below 100 and even 50 in dire times.
This is what legitimacy affects, in "Omnium Contra Omnes":
Several new decisions consider legitimacy as a requirement, old ones were reviewed to include legitimacy. Here's a list:
Now, these are aspects which increase or decrease legitimacy, modifiers and occasional occurrences:
And this is what I ate for breakfast:
effects were scaled down, they now actually consume diplomats when active: 0.1 per marriage. One can actually experience diplomats shortages in the mod (spheres, marriages, low DIP ruler). While still considerable, marriages appeal has therefore diminished. These changes benefit Muslim and Pagans who had very few candidates for royal marriages.
The Medieval Tapestery
decision is available early on, until 1450 — it's a good first option to increase legitimacy before other options (decision, prestige) become available.
, positive or negative, has a greater impact on legitimacy. While maximum prestige is an awe inspiring goal to reach in the mod, it's the second most determining factor increasing legitimacy. It must be remembered that negative prestige has a natural tendency to increase back to zero. The same is true for positive prestige which decays to zero. Uncontested claims decrease legitimacy in the long run, as they remain tied to prestige.
(Grand Marshal) and military proclivity (prestige) are the most determinant factors influencing legitimacy.
Each religious group is meant to have one decision affecting legitimacy, with varying effects. While it's possible to excommunicate countries which have the "Statute in Restraint of Appeals", these won't be affected by the negative revolt risk and legitimacy associated with excommunication — on the contrary they will reinforce their position.
All things equal, unless there are exceptional circumstances, a regency council
will last at most 15 years: that's 75 prestige lost during that duration unless it is countered.
Legitimacy doesn't decrease stability cost
modifiers anymore, as it could, in a few cases, lead to negative
stability costs. Since the underlying concept is though sound, legitimacy increases stability investment: the higher and longer lasting, the more beneficial it is on stability. Small countries are obviously advantaged from the change.
Every time a pretender
rebel stack gains control of a province, legitimacy is decreased by three.
Legitimacy is essential for Hordes survival, this aspect will be discussed in other sections.