Definition
A unit of Anglo-Saxon local governance and social organization consisting of ten neighboring families grouped together for purposes of mutual surety and law enforcement. The decennary was the foundational cell of the frankpledge system, under which members of the group were collectively responsible for one another's conduct and for producing any member accused of a crime before the courts. The head of a decennary was typically called a tithingman or borsholder.
Common Language
Modern common usage (Wiktionary): A period of ten years; a decade.
Historical common usage (Webster's 1913): Both meanings appear — a period of ten years, and a tithing of ten neighboring families (citing Burrill).
The common English meaning of decennary (a ten-year period) has entirely displaced the legal meaning in modern usage. A researcher encountering the term outside a legal or historical context will find only the temporal sense. In legal and historical sources, however, decennary refers exclusively to the social and administrative unit, not to any span of time.
Why It Matters in Research
DECENNARY is a term of pure historical English law. It will appear in sources treating Anglo-Saxon and early Norman legal institutions — primarily in commentaries on the frankpledge system, the leet court jurisdiction, and the police functions of the hundred. Researchers working in early English legal history should treat DECENNARY and TITHING as interchangeable in nearly all contexts; the distinction, if any, is of emphasis rather than substance.
Two navigational traps deserve attention. First, because the common meaning of decennary is a ten-year period, keyword searches in mixed corpora — legal histories alongside general historical or literary texts — will return substantial noise. Filtering by context (references to families, sureties, frankpledge, or hundreds) is essential. Second, the term essentially disappears from legal sources after the Norman consolidation of English administration; researchers should not expect to find it in post-medieval common law materials except as a historical reference. Its primary habitat is Blackstone, Reeve's History of English Law, and their commentators.
The connection between the decennary and the hundred is structurally important: ten decennaries typically composed a hundred, and understanding this hierarchy is necessary for tracing the evolution of local jurisdiction, tithing courts, and eventually the justice of the peace system. Corpus researchers moving from DECENNARY should follow the chain upward through TITHING → HUNDRED → LEET → FRANKPLEDGE to map the full administrative structure.
Historical Dictionary Support
All three source dictionaries are in complete agreement: Black's (both editions) and Burrill define decennary identically as a tithing composed of ten neighboring families, and all cite the same two authorities — Reeve's History of English Law and Blackstone's Commentaries (1 Bl. Comm. 114). There is no divergence among the sources on this point.
Burrill adds the Latin form decenna, which is useful for researchers working in medieval Latin legal manuscripts or Year Book materials where the vernacular English term may not appear.
What the historical dictionaries do not address is the functional dimension of the decennary — the mutual surety obligations, the role of the tithingman, and the relationship to View of Frankpledge. For that, the dictionaries serve only as a starting point; Blackstone and Reeve must be consulted directly.
Jurisdictional Note
DECENNARY is a term of English law only. It has no counterpart in Scots law, civil law systems, or American law, where the frankpledge system was never transplanted. American legal dictionaries include it solely for its historical and comparative value.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Frankpledge; Tithing; Hundred (administrative unit); Anglo-Saxon Legal Institutions