Definition
In feudal law, aribannum is a monetary fine imposed on a vassal or subject who failed to answer the king's summons to military service. The penalty recognized the foundational feudal obligation of military service and converted breach of that duty into a financial sanction collectible by the crown.
The term is closely associated with the related concept of ARIERBAN (also spelled ARRIÈRE-BAN), an edict issued by the ancient kings of France and Germany commanding all vassals, the nobility, and the vassals' own vassals to take up arms. Refusal to comply risked forfeiture of estates. Aribannum, by contrast, names the specific fine rather than the edict itself — the financial consequence of non-compliance, not the command.
Common Confusion
Aribannum and arierban are consistently run together in historical sources, including in Black's own entries, which define both terms within the same passage. The distinction matters: arierban is the royal proclamation compelling military muster; aribannum is the penalty assessed when a subject failed to obey it. A researcher encountering either term in a feudal record is looking at two sides of the same obligation — the command and the consequence of defiance.
Why It Matters in Research
Aribannum appears almost exclusively in medieval and early modern feudal contexts, and its presence in primary sources is a signal that the document touches on military tenure obligations, the structure of feudal land-holding, or the fiscal administration of the crown's war-making power. Researchers should be aware of several navigational points:
First, the term is encountered far more often in legal dictionaries and glossaries than in primary legal records available in English-language corpora. Its natural habitat is the Latin administrative and chronicle literature of Carolingian and post-Carolingian Europe, which means Law Mind researchers working in English common law sources are unlikely to encounter aribannum in operative documents. When it does appear, it is typically in a treatise or dictionary passage tracing feudal antecedents.
Second, the term has no meaningful survival into modern law. Unlike some feudal concepts that were transmuted into modern doctrines (distress, seisin, tenure), aribannum was rendered obsolete by the commutation of military service obligations and the professionalization of armies. No modern legal equivalent exists.
Third, the entry in Black's places aribannum and arierban side by side, which can create indexing confusion. A researcher searching for either term may need to cross-check under both headings in historical dictionaries, as editorial choices about placement varied across editions.
Fourth, the citation to Spelman — appearing in Black's and in Bouvier — refers to Sir Henry Spelman's Glossarium Archaiologicum, the standard early modern authority on feudal and ecclesiastical terminology. Spelman is a real and legitimate source, and his glossary remains a useful reference for the deeper etymological and historical background of terms like aribannum and arierban that legal dictionaries treat only briefly.
Historical Dictionary Support
Black's (1st and 2nd editions) and Bouvier's are in substantive agreement on the core definition: aribannum is a fine for failure to join the army upon the king's summons. All three sources treat it as a term of feudal law and do not suggest any survival into common law practice.
The entries in Black's embed aribannum within a passage that immediately pivots to arierban, treating the two concepts as companion terms. This editorial choice is instructive — the compilers understood aribannum as intelligible only in relation to the broader system of royal military summons.
Bouvier's entry is slightly shorter and omits the arierban connection, proceeding instead to a separate entry on ARIMANNI (possessors of lands derived from their lords). This sequencing reflects Bouvier's alphabetical structure but may cause researchers to miss the aribannum-arierban relationship unless they cross-reference.
None of the three dictionary sources provide doctrinal elaboration or case authority, which is expected: by the time these dictionaries were compiled, aribannum had no living legal application. The entries function as historical glosses rather than operative legal definitions.
Jurisdictional Note
Aribannum is a term of continental feudal law — primarily French and German in origin — and has no recognized place in English common law doctrine. It appears in English-language legal dictionaries solely as a matter of historical and comparative completeness. Researchers working on English feudal tenure should look instead to analogous English concepts such as escuage (scutage), the financial commutation of knight service obligations, which served a functionally similar purpose within the English system.