Minor holdings in occupied counties are also usurped. Invasion-type wars usurp occupied territory in addition to the war's stated target.They try to make the current rulers into vassals, but usurp if they cannot, due to the attacker's low rank or the defender holding territory elsewhere. De jure wars on counties, as well as subjugation-type wars, vassalize or usurp the target titles.
Warfare is a primary way to expand your realm, as most CBs can give you new territory:
