Assimilating a faction costs you Influence points. You may have to wait a few turns until you have
the necessary points, then open the Empire Screen to manage your assimilated faction.
Assimilating a faction has many benefits:
It provides you with a new unit type, which can complement your own faction’s units
It provides beneficial trait(s) to your empire. Some traits depend on the number of pacified
villages you control; this encourages the player to pacify as many villages of this Minor
Faction as possible in all the regions of the world.
There is a limit of the number of Minor Factions you can assimilate (only 1 at the beginning of the
game), and even though this limit is increased with research, you should still be careful about
choosing the most useful Minor Faction for your empire.