Definition
To bastardize is to declare, adjudicate, or prove a person to be a bastard — that is, illegitimate, born outside of lawful marriage and therefore outside the legal status that attached to legitimate birth. The term operates in two related but distinct senses in legal usage:
1. Judicial act. A court bastardizes a child when it formally adjudicates that the child was not born in lawful wedlock and is therefore illegitimate. This was not merely a factual finding but a legal status determination with cascading consequences for inheritance, name, and family membership.
2. Evidentiary act. A party bastardizes a child when they offer evidence in a proceeding to prove illegitimacy — for example, challenging a child's right to inherit by attacking the legitimacy of birth.
The distinction matters because the two senses arise in different procedural postures: one is what a court does in its judgment; the other is what a litigant does in building a case.
Common Language
Modern common usage (Wiktionary): To claim or demonstrate that someone is a bastard or illegitimate; to reduce something from a higher to a lower state by removing refined elements or introducing debased elements; to beget out of wedlock.
Historical common usage (Webster's 1913): To make or prove to be a bastard; to stigmatize as a bastard; to declare or decide legally to be illegitimate. Also, rarely, to beget out of wedlock.
The legal meaning is narrower than the common meaning in one important respect and broader in another. Common usage has expanded "bastardize" metaphorically to mean degrading or corrupting anything — a bastardized version of a recipe, a tradition, a text. Legal usage never carried this sense. Conversely, the legal sense of formal adjudication by a court is more precise than the colloquial sense of merely calling someone illegitimate.
Common Confusion
Bastardize is sometimes treated as synonymous with a finding of illegitimacy, but the terms describe different moments in a legal proceeding. Illegitimacy is the status; bastardization is the act of establishing or declaring that status. A related confusion arises from the passive construction: a child is not automatically bastardized by circumstances of birth — the legal status required a proceeding or formal determination in the common law system. Additionally, the maxim embedded in the historical sources — that a mother cannot bastardize her own child — reflects a specific evidentiary rule: a wife was not permitted to testify to facts that would render her child illegitimate, notably by admitting non-access by her husband. This rule of evidence is sometimes mistaken for a rule of substantive law preventing illegitimacy findings altogether.
Why It Matters in Research
Researchers working in probate, inheritance, and family law sources from the eighteenth through early twentieth centuries will encounter this term in its strict technical sense. The stakes of bastardization were severe under the common law: a bastard was filius nullius — the son of no one — incapable of inheriting from either parent by descent, incapable of transmitting heritable blood, and outside the ordinary protections of family law. Any case or treatise touching on disputed inheritance, legitimacy proceedings, or bastardy examinations (the separate poor law proceeding to identify the father of an illegitimate child for support purposes) may use bastardize in either or both senses.
The maternal disqualification rule — that a wife cannot bastardize her child — appears repeatedly in historical sources and has a distinct procedural life in English and early American courts. Researchers should not conflate this evidentiary bar with modern rules governing parentage testimony.
The term has lost most of its legal currency. Modern statutes governing parentage, legitimacy, and child status have largely replaced the common law vocabulary, and "bastardize" rarely appears in contemporary American judicial opinions or statutory text. When it does appear in modern sources, it is almost always in the colloquial sense of corruption or degradation, not the legal sense of status adjudication. Researchers must be alert to this shift when moving between historical and contemporary materials.
The two Latin maxims preserved in both Black's editions — Bastardus nullius est filius, aut filius populi and Bastardus non potest habere hæredem nisi de corpore suo legitime procreatum — are operative rules of the common law of descent, not merely descriptive phrases. They surface in inheritance disputes and legitimacy challenges well into the nineteenth century and provide useful anchors for tracing the doctrine.
Historical Dictionary Support
Both editions of Black's Law Dictionary are in close agreement. Each identifies the two legal senses — judicial declaration and evidentiary proof — and each explicitly preserves the rule that a married mother cannot bastardize her own child. The second edition adds the fuller procedural framing ("to give evidence to prove one a bastard"), making the evidentiary sense slightly clearer.
Both editions attach the same two Latin maxims without significant variation, drawing on Travers's Latin Maxims (Tray. Lat. Max. 51) for the second. Webster's 1913 corroborates the legal meaning and adds the useful Blackstone quotation illustrating the temporal rule: a child born in lawful wedlock is presumed legitimate even if conceived before the marriage, and the law does not bastardize such a child. This point — that birth in wedlock, not conception, governed the presumption — is substantively important for reading historical probate and legitimacy records and goes slightly beyond what either Black's edition addresses directly.
What the historical dictionaries collectively understate is the procedural context: bastardization occurred in different forums (ecclesiastical courts, common law courts, chancery, and bastardy examinations under poor law statutes), and the rules governing who could bring such a proceeding and what evidence was admissible varied across these forums. Researchers should not assume the term carries uniform procedural content across all historical sources.
Jurisdictional Note
The common law rules governing bastardization were substantially uniform across English-derived jurisdictions, but American states varied in how far they retained the ecclesiastical court tradition and in the procedural vehicles available for legitimacy challenges. Some states addressed legitimacy through dedicated statutory proceedings; others folded it into probate or equity jurisdiction. Researchers working in Louisiana, which followed civil law, will find a distinct framework for legitimacy and filiation that does not map cleanly onto the common law vocabulary of bastardization.