Vassalage, Vassal-Liege, or Liege-Vassal relationship is a special diplomatic relationship in which one Empire is subordinated to another.
Vassals can be made when an Empire surrendered in a war; "Become a Vassal to [the winning empire]" can be picked in the Surrender Terms. If imposed, the losing Empire is now a Vassal, and the winning Empire is now a Liege.
The Vassal must provide a tribute to the Liege in the form of Money per turn.
The Liege controls the Diplomatic States, State Religion, and Treaties of its Vassal. Treaties negotiated with a Liege will be applied to its Vassals as well, and declaring war on a Liege will also drag its Vassals into the same war.
- On the other hand, Grievances and Demands caused or received the Vassal must be handled by the Liege.
The Strategic and Luxury Resources of the Vassal and the Liege are shared. The Liege can have access to its Vassal's Resources, and the Vassal can have access to its Liege's Resources as well. No purchase or trade routes can be established between the two due to the sharing.
The Liege can liberate its Vassal using the Grant Freedom button on the Relation Tab. The Liege will lose any Resource access or tribute it had from the Vassal, and the Vassal will have diplomatic freedom once again. All the Treaties between the two need to be renegotiated.
The Vassal can also Demand their freedom from the Liege. If the Liege refused the Demand, the Vassal and Liege will go to war.
Vassal or Vassal-leige territory is considered "allied", allowing benifits such as healing your units.
The British culture, when being a Liege, can also build their Colonial Office Emblematic District in their Vassals' Territories.
Treaties between Liege and Vassal[]
Cost of Vassalization[]
The cost can be calculated using following formula:
Cost = 125 + 35 * C - Min(5.000 * Max((YF - OF) / 200.000, 0)), 120)
C = Opponent's Cities
YF = Your Fame
Additional information: