Definition
Jus necis (Latin: "right of death") is a concept from Roman law referring to the legal power held by a Roman paterfamilias — the male head of household — to put to death members of his family subject to his authority, most notably his children. It existed as one half of the broader power known as jus vitae necisque: the right of life and death. Under this power, a father held near-absolute dominion over the lives of those within his patria potestas, the juridical authority of the Roman household head. The right was ancient even by classical Roman standards, rooted in the earliest periods of Roman legal development, and was progressively constrained and ultimately abolished as Roman law matured under the Empire.
Jus necis is not operative law in any modern legal system. It appears in legal dictionaries and scholarship as a historical term of Roman law, relevant to understanding the structure of Roman family law, paternal authority, and the conceptual origins of legal personhood.
Common Confusion
Jus necis is inseparable from its counterpart, jus vitae — the right of life. The two are most properly treated as a unified concept, jus vitae necisque, meaning the complete power over life and death. Bouvier's Law Dictionary redirects jus necis entirely to that combined entry. Researchers should be aware that some sources treat them as a single doctrine while others, including both editions of Black's, define jus necis as a standalone entry. The concepts are not truly distinct; jus necis without jus vitae is an analytical fragment.
Do not confuse jus necis with related but separate Roman law concepts such as jus exponendi (the right to expose newborns) or the power of sale (mancipium). These were distinct exercises of paternal authority, even if they shared the same structural foundation in patria potestas.
Why It Matters in Research
Jus necis appears in legal history research primarily in two contexts: studies of Roman family law and patria potestas, and broader comparative or philosophical treatments of legal personhood and state-sanctioned private authority.
Researchers working in Roman law sources should note the progressive erosion of this right across Roman legal history. By the classical period it was rarely exercised without risk of social or legal sanction; by the late Empire, imperial constitutions had effectively abolished it. Sources that treat jus necis as a straightforward, continuously operative right flatten this evolution and should be read with caution.
Burrill's entry is notably corrupted in the surviving text: the definition begins with Roman law but then splices in an unrelated passage concerning ecclesiastical jure patronatus procedure (a "commission from the bishop" and a jury of clergymen and laymen). This appears to be a typographical or binding error in the source — material from a neighboring entry has run into the jus necis definition. Researchers relying on Burrill for this term should disregard the second half of that entry entirely.
Black's first and second editions are substantively identical here, differing only in a minor citation discrepancy (Hob. 146 versus Hob. 148) that likely reflects a page reference error in one edition rather than a meaningful textual variation.
For historians and legal theorists, jus necis is also a reference point in scholarship on the limits of private authority versus state power — when and how Roman law transferred the monopoly on legitimate killing from the household to the state. That trajectory has influenced modern comparative constitutional arguments about state authority and individual rights.
Historical Dictionary Support
All four source dictionaries agree on the core definition: jus necis is the right of death, specifically a father's power over his children in Roman law. The entries are brief and largely identical across Black's first and second editions.
Bouvier takes the most analytically defensible approach by declining to define jus necis independently and directing the reader to jus vitae necisque. This reflects sound legal history: the ancient sources treat the power as unified, and disaggregating it into "right of life" and "right of death" as separate entries risks implying they were exercised or conceived independently, which they were not.
Burrill adds a citation to Gibbon's Decline and Fall of the Roman Empire — a historiographical rather than legal primary source — which signals that even nineteenth-century legal lexicographers were reaching outside strictly legal texts to explain this concept. This is appropriate given that jus necis is more a historical artifact than a technical legal rule with a developed jurisprudence in classical sources.
None of the historical dictionaries engage with the gradual abolition of the right under imperial Roman law, nor with the scholarly debate over how often and under what circumstances the right was actually exercised versus existing as a formal legal power seldom invoked. Researchers should not treat these dictionary entries as a complete account of the doctrine's history.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Patria Potestas; Roman Family Law; Jus Vitae Necisque