A free mod for Mount & Blade II: Bannerlord, by Splintert.

DynaCulture is a mod for Mount & Blade II: Bannerlord that adds a dynamic simulation of settlement culture and influence based on the owning kingdom or clan. The primary effect is that expanding a kingdom’s territory will expand its influence, affecting neighboring settlements and eventually causing them to flip to the kingdom’s culture.

The mod works by creating a random map for the player to start with. The player will then choose a starting location and create their own kingdom or clan. Once the player is already in control of his own kingdom, he will have to start expanding its influence.