The first sovereignty perimeter: the condition in which an entity is reliably identified, disambiguated, and characterized by AI systems when asked ‘who is X?’ Achieved through KGMID assignment, comprehensive schema.org Person/Organization markup, Wikidata entity creation, and consistent NAP across authoritative directories. Identity sovereignty is prerequisite to domain and vocabulary sovereignty: if AI systems cannot reliably identify who you are, they cannot reliably characterize what you do or what you mean. Most organizations have identity sovereignty or are close to it; it is the least contested perimeter.