Definition
Spurii (singular: spurius) is a Roman and civil law term designating children born of illicit or disreputable unions — most narrowly, children conceived in prostitution or of a mother whose partner is entirely unknown. More broadly, the term was used in civil law tradition to describe a category of illegitimate children whose status was considered the most degraded among those born outside lawful marriage, distinguishing them from children of concubinage or of a void but putatively valid marriage.
In classical Roman law, spurii occupied a distinct position within the hierarchy of illegitimate birth. Because their father could not be identified or legally acknowledged, they took the status of their mother alone and had no cognatic or agnatic connection to a paternal family. This made them subject to the harshest civil disabilities: they could not inherit from a father, claim the father's citizenship or rank, or benefit from paternal succession absent specific testamentary provision.
The term carried over into medieval canon law and into the civil law systems of continental Europe and those American jurisdictions influenced by the civil law tradition, particularly Louisiana.
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Common Confusion
Spurii is sometimes used loosely as a synonym for all illegitimate children (bastards), but the terms are not coextensive. In civil law systems, illegitimacy was subdivided: natural children (nati ex soluto et soluta, born of two unmarried but legally capable persons) occupied a higher status and could be legitimated by subsequent marriage. Spurii, by contrast, were born of unions incapable of producing even natural children with recognizable paternal ties — chiefly prostitution or anonymous connection — and could not be legitimated in the same manner. The distinction matters in historical sources because rights of legitimation, inheritance, and name-taking differed sharply across these subcategories.
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Recognized Forms
/SUBTYPES
Within the civil law taxonomy of illegitimacy, spurii sit at one end of a spectrum:
NATURAL CHILDREN: Born of two unmarried persons free to marry each other. Capable of legitimation by subsequent marriage or royal/judicial rescript.
SPURII: Born of prostitution or unknown paternity. Not capable of legitimation by subsequent marriage in classical civil law; no paternal filiation established.
NOTHI (or NOTHII): A related civil law category sometimes used to describe children of concubines, occupying a middle position. Usage varied across periods and jurisdictions.
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Why It Matters in Research
Researchers encounter spurii most frequently in three contexts: Roman law sources and their commentaries, civil law treatises on personal status and succession, and Louisiana legal materials where the civil law tradition persisted after American acquisition.
The primary research trap is anachronism. Common law sources — English and American — rarely used spurii as a term of art, defaulting instead to bastard or illegitimate. When a civil law source distinguishes spurii from natural children or nothi, the distinctions carry real legal consequences for inheritance, legitimation, and capacity that a common law framework would not capture. A researcher reading a civil law succession dispute through a common law lens may miss that the child in question was categorically ineligible for legitimation, not merely technically illegitimate.
In Louisiana materials, the antebellum Civil Code drew directly on civil law categories of illegitimacy, and the distinctions among natural children, adulterine bastards, and spurii shaped inheritance rights in ways that diverged significantly from common law states. Post-Reconstruction amendments to Louisiana family law progressively collapsed these distinctions, so the term's significance is concentrated in pre-Civil War Louisiana jurisprudence and the commentaries that surrounded it.
For Roman law research specifically, spurii appear in the Institutes of Justinian and in Sandars's edition of the Institutes (cited in Rapalje & Lawrence as Sandars's Institutes, 5th ed., p. 366), making that source a useful starting point for primary authority.
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Historical Dictionary Support
Rapalje & Lawrence defines spurii as "children conceived in prostitution," citing Sandars's Institutes. The entry is brief and accurate as far as it goes, but it captures only the narrowest civil law definition — the prostitution case — without conveying the broader civil law usage that extended to any child of entirely unknown paternity. This is a meaningful omission for researchers working with continental civil law sources or canonical commentary, where spurii encompassed the full category of children lacking any identified or identifiable father, not only those born of sex work.
No other source dictionary was provided for this entry. Researchers should consult Sandars's Institutes directly for the Roman law foundation, and Planiol's Treatise on the Civil Law for the French civilian tradition that influenced Louisiana.
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Jurisdictional Note
The term has practical legal significance primarily in Louisiana, where the civil law tradition historically recognized formal subcategories of illegitimacy drawn from Roman and French sources. Common law jurisdictions did not adopt the civil law taxonomy; in those jurisdictions, spurii has no technical legal meaning and appears only in academic or historical context.
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