Definition
Postnati (singular: postnatus) is a Latin term meaning "those born after." In legal usage, it refers to persons born after a particular event, date, or legal change that carries significance for their status, rights, or citizenship. The term functions as a status classifier — identifying a cohort of persons whose legal condition differs from those born before the same threshold event.
The term appears most prominently in historical debates over the legal status of persons born after a change in sovereign rule or political union. The paradigm case is the question of whether persons born in Scotland after the union of the English and Scottish crowns under James I in 1603 (the antenati/postnati division) were natural-born subjects of the English crown. Postnati in that context were held to acquire subject status by virtue of having been born under the same sovereign, while antenati — those born before the union — remained in a more ambiguous category.
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Common Confusion
POSTNATI vs. ANTENATI: These two terms are paired opposites and must be understood together. Antenati refers to those born before the relevant event; postnati to those born after. In historical citizenship and allegiance disputes, the legal consequences could be sharply different for each group. A researcher encountering one term in a source should immediately investigate how the source treats the other.
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Why It Matters in Research
This term belongs to a specific and largely historical body of law concerning natural-born status, allegiance, and the effect of political changes on personal legal status. Researchers will encounter postnati most often in three contexts:
First, in early English common law materials and constitutional debates about the nature of allegiance. The Calvin's Case (1608) discussion is the locus classicus — it turned in significant part on the distinction between postnati and antenati and established that postnati of Scotland born after James I's accession to the English throne were natural-born subjects of England. Any corpus materials touching on Calvin's Case or early allegiance doctrine will invoke this term.
Second, in American legal history during and after the Revolutionary period. The postnati/antenati framework was applied — sometimes clumsily — to questions about the citizenship status of persons born before versus after American independence. Treatise writers and courts used the terminology to work through whether birth under the crown of Britain conferred continued allegiance or whether independence severed that tie. Researchers in post-Revolutionary citizenship and naturalization materials should expect to see the term used in this adapted context.
Third, in Reconstruction-era debates about birthright citizenship and the Fourteenth Amendment. The historical common law framework, including postnati analysis, furnished background legal vocabulary that participants in those debates drew upon.
The trap for researchers: postnati does not have a fixed referent. The "event" after which persons are born must be identified from context. Different sources will use the term with reference to entirely different threshold events — a change in sovereign, a declaration of independence, a territorial annexation, a constitutional change. Always identify the triggering event before interpreting a source's use of postnati.
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Historical Dictionary Support
Black's Law Dictionary (2nd Ed.) provides only a bare cross-reference entry ("Post Natus. Those born after. See —"), offering the Latin root and a pointer without substantive elaboration. This is not unusual for terms whose content was carried primarily in case law and treatise discussion rather than statutory definition.
The historical dictionaries are of limited value here precisely because postnati is a term whose meaning is entirely context-dependent. Its legal significance is not in its definition — which is simply "those born after" — but in the framework of allegiance, sovereignty, and status into which it is inserted. Researchers should not expect the dictionary shelf to carry the analytical weight; it sits in the common law reports and the citizenship treatises.
Wiktionary's definition ("those born after a certain event") is accurate as far as it goes and for once does not diverge from the legal usage in any problematic way. The legal term is simply the common meaning applied to a specific doctrinal context.
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Jurisdictional Note
The postnati doctrine developed principally in English common law and was transplanted into early American legal thought. It has no significant modern statutory presence in any U.S. jurisdiction. Its relevance today is almost entirely historical and constitutional — primarily as background to understanding birthright citizenship doctrine and early allegiance theory.
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Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Allegiance; Natural-Born Subject; Calvin's Case; Birthright Citizenship.
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