Definition
Lianum is a Latin term appearing in Roman and civil law as an abbreviated reference to the Senatus Consultum Trebellianum — the Trebellian decree of the Roman Senate. Enacted during the consulate of Trebellius Maximus and Annaeus Seneca in the reign of the Emperor Nero, the decree addressed a procedural gap in the law of fideicommissary inheritances (inheritances transmitted under a trust-like obligation). Under prior Roman civil law, when an heir was required to restore an inheritance to a third party pursuant to a fideicommissum, the legal actions available to or against the heir could not automatically be pursued by or against the beneficiary who received the restored estate. The Trebellian decree corrected this by directing that all civil law actions which could be brought by or against the heir were to be transferred to and enforceable against the person to whom the inheritance was actually delivered. The term "lianum" functions as a shorthand label — derived from the name of the consul Trebellius — for this senatorial enactment and the legal regime it established.
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Why It Matters in Research
This term is encountered almost exclusively in civil law contexts and in scholarship engaging Roman law sources directly. Researchers in common law traditions will rarely encounter it except in comparative law materials, historical treatises on trust and succession, or annotated editions of Justinian's Institutes and Digest.
The key navigational point: lianum appears as a compressed reference and may be encountered without full explanation in older civil law commentaries and glossaries. Researchers should recognize it as pointing to the Senatus Consultum Trebellianum and cross-reference that full term when searching the corpus. Entries under "Trebellianum," "fideicommissum," and "senatus consultum" will carry the substantive doctrine; lianum is essentially a locator term.
Note also that both Black's and Burrill's entries embed the term within the header SENATUS CONSULTUM TREBELLIANUM (Black's truncates to "SENATUS CONSULTUM ULTIMÆ" in the printed entry, which reflects either a typographic error or page-break artifact in the source edition). Researchers using digitized versions of these dictionaries should be alert to OCR corruption or incomplete capture of the full header, which may cause the entry to appear disjointed or misattributed.
The doctrine itself — the transfer of heirs' actions upon restoration of a fideicommissary inheritance — has a parallel in later civil law jurisdictions' treatment of succession and universal transfer. Civilian lawyers working in Louisiana, Quebec, Scotland, or South Africa may encounter the Trebellian decree in succession treatises as a doctrinal ancestor.
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Historical Dictionary Support
Black's and Burrill's agree on the substance: both identify lianum as a Latin abbreviation for the Trebellian senatus consultum, both note its enactment under Trebellius Maximus and Annaeus Seneca in Nero's reign, and both cite the same institutional authority (Institutes 2.23.4 and Digest 36.1). Burrill's entry is marginally fuller, naming both consuls explicitly and situating the enactment within the reign of Nero — details that Black's compresses.
Neither dictionary engages the subsequent modification introduced by the Senatus Consultum Pegasianum, which complicated the Trebellian scheme by introducing a rule that required the heir to accept a minimum quarter share before the Trebellian transfer of actions would operate. Researchers working on the full arc of Roman fideicommissary law should not treat these dictionary entries as complete accounts of the doctrine.
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Jurisdictional Note
Lianum and the Trebellian decree have no direct application in common law jurisdictions. In civil law systems with Roman-derived succession codes — particularly Louisiana and Quebec — the underlying doctrine has historical relevance to universal succession theory, though modern codes address the matter by statute without reference to the Roman decree by name.
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