Nomad agitation is a mechanic that makes it difficult for non-nomads to conquer land with no castles or cities from nomads.
Counties conquered by non-nomads from nomadic realms get the "nomad agitation" modifier if:
- they do not have any castles or cities OR
- they were previously conquered by the nomad and the original holdings have been completely destroyed.
The modifier causes the province to revert to nomadism on the death of the top liege, unless:
- The province has a castle or city OR
- (if the top liege is tribal) The province tribe has two upgrades (these can be a combination of any upgrades, e.g. Earth Hillfort I and Market Village I)
In addition to becoming nomadic, these provinces will try to join an adjacent nomadic realm (if the ruler shares their culture). The Khagan of the adjacent realm will receive a notification and a new vassal clan.
The modifier also increases the revolt risk of the province.
Removal of the modifier
The modifier can be removed by most culture conversion events.
Immortal characters can rest easy, knowing that the modifier lasts a mere 100 years.
A nomadic ruler who reclaims the county can remove the modifier using the Reclaim Nomadic County title action, which also usurps the county.
The simplest solution is to build a castle or city directly. This costs about 500 wealth, but you may be able to convince a wealthy feudal vassal to pay the cost instead of you.
A more economical approach is to build Hillfort IV in the tribe. This costs only 375 wealth and usually creates a full set of (castle + city + temple) replacing the tribe upon Upgrade tribe or Adopt feudalism. However, it takes 4 years to build Hillfort IV from scratch, and the investment can be lost due to unexpected death.
Even more economical is to build a Hillfort IV in single tribe, and give it to a tribal vassal to use as their capital county. When they adopt feudalism, their entire demesne will be converted from tribes to castles. Try to pick the duchy capital, since dukes tend to move there if they can. Alternatively, pick a county that already has hillfort progress, but ensure the vassal cannot create the duchy title. A vassal with high stewardship is ideal, because they can hold many counties without feeling they need to give one away.
Tribal vassals with Hillfort IV in their capital will usually adopt feudalism within about a year, assuming they share their direct liege's culture group and exact religion.
Countermeasures as a nomad
If playing as a nomad, be on the lookout for nomad agitation in neighbouring realms; the AI rarely manages to keep nomadic counties during succession, offering a chance to grab additional land. As a Khagan, you may even have a new vassal clan joining you, although this may not be a good thing.
Completely destroying all holdings in a county ensures that the "nomad agitation" modifier will be present.