Tenet

Matrimonium Sacrum

tenet_divine_marriage

O Lord, it was not for lust that we were joined in this sacred union, but with sincerity and in truth. Grant that we may find mercy and grow old together, preserving the sanctity of our bond. Et nunc Domine, tu scis quia non luxuriae causa accipio sororem meam, sed sola posteritatis dilectione, in qua benedicatur nomen tuum in saecula saeculorum. Matrimonium Sacrum Historical Background

Effects

Followers

Spouse Opinion+10
Chance of new good Congenital Traits+15%
Chance of new bad Congenital Traits+15%
Chance of inheriting good Congenital Traits+15%
Chance of inheriting bad Congenital Traits+15%
Chance of reinforcing Congenital Traits+10%

Other effects

The Monogamous marriage bonus also grants a large amount of Piety if you are marrying a Close Family member
Adherents are significantly less likely to create or join Factions against a Liege married to Close Family or Extended Family

Virtues and sins

Virtues

Pure-blooded
Incestuous
Loyal

Faiths that start with it

Mazdayasna

Source: game/common/religion/tenet_types/00_tenet_types.txt and the English localisation, Crusader Kings III 1.20.0.3.