A vassal is a country under the power of other country, made by the player or by the AI, the latter of which does so very rarely. Vassals exist in both the original Age of Civilizations and its sequel, Age of History II, both of which share differing mechanics on vassals.
Ways to get a vassal
- Peace Negotiations.
- Offer vassalization to a country
- Having a nonexistent country's capital (only AoC).
- Creating a new country (Only AoH2)
The vassals will always have their lord's flag aside from their name, and the type of government's image will be modified. They can be called for fight in a war, like allies and it's much easier to make unions with them.
Lords can tax their vassals, which is called a Tribute. The lords can change the amount of taxation on their vassals, but this can affect the Liberty Desire (see below). Any country can have a vassal, so a lord can be also a vassal from another country.
Since AoH2, the vassals are independent from the lord (the player cannot control them), have their own wars and being capable of expanding.
A characteristic from AoH2; every vassal has it: Liberty Desire. Depending on the lord's relations before the vassalization, the initial Liberty Desire can be 0% when they had a good relationship (like +30) or 55% because of their very bad relationship (like -25). Liberty Desire is also increased by High Tributes.
Once Liberty Desire gets high, the lord may involuntarily be swung to liberate the vassal or, possibly worse, declare war on the vassal to maintain control.
Liberty Desire can change with actions made by the player, making a positive relationship and a more cheap tribute can decrease the Liberty Desire, but making the contrary can increase it.
In AoH2, a country can stop being a vassal if:
- The vassal chooses the diplomatic action to declare independence. Note that this has an absurdly high chance for the lord to declare war.
- The lord liberates the vassal.
- The lord receives and accepts an ultimatum that demands the liberation of the vassal.
- The lord liberates the vassal during peace negotiations. (Note that this usually only happens if the lord loses a war, but can also happen in other, rarer scenarios.)