Definition
In Roman law, the septunx is a fractional unit representing seven-twelfths (7/12) of a whole. It is a division of the as — the Roman standard unit of measure used in law for inheritance, property, and debt — consisting of seven unciae (singular: uncia), the as being divided into twelve equal parts.
The term appears in Roman private law primarily in the context of inheritance shares and the apportionment of estates among co-heirs. When a testator divided an estate using the duodecimal system of the as, a legatee or heir receiving a septunx took seven of the twelve notional parts of that estate.
Core Elements
The septunx is best understood within the Roman duodecimal framework:
- The as: the whole unit, divided into 12 unciae
- The uncia: one-twelfth (1/12) of the as; the base fractional unit
- The septunx: seven unciae, or 7/12 of the as
- Complement: the remaining five unciae (5/12) constitute a quincunx
This system was applied not only to monetary values and weights but also to real property (land measures) and testamentary shares. A co-heir could receive any named fraction of the as; the septunx was one of the standard named fractions in that vocabulary.
Recognized Forms
/SUBTYPES
The named fractions of the as form a structured series. For research context, the principal divisions are:
- Uncia: 1/12
- Sextans: 2/12 (1/6)
- Quadrans: 3/12 (1/4)
- Triens: 4/12 (1/3)
- Quincunx: 5/12
- Semis (or semissis): 6/12 (1/2)
- Septunx: 7/12
- Bes (or bessis): 8/12 (2/3)
- Dodrans: 9/12 (3/4)
- Dextans: 10/12 (5/6)
- Deunx: 11/12
- As: 12/12 (the whole)
Why It Matters in Research
Researchers encounter septunx almost exclusively in two contexts: Roman law sources (particularly those dealing with succession and the lex Falcidia) and English legal dictionaries that reproduced Roman law terminology during the period when civil law scholarship was integral to common law training. Its appearance in Black's signals that nineteenth-century American legal education still expected practitioners to command this vocabulary, even if the term had no direct operative function in American common law practice.
The trap for corpus researchers is treating septunx as a live term in any common law jurisdiction. It is not. If septunx appears in an American or English legal document outside a treatise or dictionary, the document is almost certainly either a translation of a Roman or civil law text, a scholarly gloss, or an inheritance instrument drafted by a civilian-trained lawyer drawing on continental practice.
In inheritance research specifically, the duodecimal fractions of the as were the vehicle by which Roman testators expressed partial shares. A testator who left a septunx to one heir and a quincunx to another had divided the estate completely (7/12 + 5/12 = 12/12). Researchers working with civil law jurisdictions — Louisiana, Quebec, or sources grounded in the Corpus Juris Civilis — may encounter these fractions in substantive legal analysis rather than merely as historical curiosities.
The reference to Taylor's Civil Law (Tayl. Civil Law, 492) in both Black's editions is consistent: this is John Taylor's Elements of the Civil Law, a real treatise, and the citation is reliable as a bridge to deeper Roman law treatment of the as system.
Historical Dictionary Support
Both the first and second editions of Black's Law Dictionary give virtually identical entries, differing only in minor typographical presentation. Both define septunx as a division of the as containing seven unciae, cite the proportion as seven-twelfths, and anchor the definition to Taylor's Civil Law at page 492. There is no divergence between the two editions on substance.
What neither Black's edition develops is the breadth of septunx beyond law. The Latin dictionary record shows the term in Columella (agricultural land measurement), Livy (weight of gold), and Martial (cups of wine in drinking customs). The legal and non-legal uses share the same arithmetic core — seven of twelve — but the legal editions sensibly restrict the definition to the Roman law of property and succession, where the term had operative significance. Researchers should note that this narrowing is appropriate; the non-legal uses are irrelevant to legal corpus work.
Neither edition of Black's addresses the lex Falcidia, the Roman statute that guaranteed an heir at least one-quarter (three unciae, or a quadrans) of the estate, which is the most important legal context in which precise fractional vocabulary including the septunx could become outcome-determinative. That gap is worth noting for researchers who need to understand why Roman lawyers cared about exact fractional names at all.
Jurisdictional Note
The septunx has no operative function in common law jurisdictions. It retains marginal relevance in civil law systems whose succession rules derive from Roman law, including Louisiana and mixed jurisdictions. Even there, modern codes express fractional shares in decimal or percentage terms rather than through the as system.