Definition
A Latin legal term from old English and commercial law with two related meanings:
1. (Old English law) To make secure; to give security or assurance by providing pledges or sureties. The act of securing an obligation through the interposition of a pledge (pignus) or a guarantor (fidejussor).
2. (Commercial law) To insure or assure; the act of providing insurance coverage. In this commercial sense, adsecurare functioned as the verbal root of adsecuratio, the Latin term for insurance or assurance of goods, particularly in maritime contexts.
Both meanings share the same root concept: making something safe or certain against risk or default, whether through personal surety in the feudal sense or through contractual indemnity in the commercial sense.
Why It Matters in Research
Researchers will encounter adsecurare almost exclusively in two distinct documentary contexts, and conflating them produces analytical errors.
The old English law usage appears in medieval charters, plea rolls, and formularies where the giving of pledges was a routine procedural requirement. When a source uses adsecurare in this context, the researcher should look for accompanying references to plegii (pledges) or fidejussores (sureties), as the term signals a formal obligation backed by named individuals — not merely a promise. Spelman's Glossarium and Hoveden's chronicle materials, cited in Burrill, situate this usage firmly in the post-Conquest administrative and feudal record.
The commercial law usage bridges into early insurance history. Adsecurare in this sense connects to the lex mercatoria tradition and to continental European commercial practice, particularly the maritime insurance instruments that circulated in the Italian and Hanseatic trading communities before English statutory insurance law developed. Burrill's cross-reference to Loccen's de Jure Maritimo places adsecurare within the scholarly literature on sea law, where assecuratio was the standard term for the insurance contract. Researchers tracing the doctrinal lineage of insurance law back through its Romano-canonical and civilian roots will find adsecurare and adsecuratio functioning as technical terms in that literature.
The practical research trap: a document using adsecurare in a medieval English charter context means something procedurally and substantively different from the same term appearing in a sixteenth- or seventeenth-century treatise on maritime commerce. The shared etymology obscures what are, in practice, two different legal institutions — suretyship and insurance — that happen to share a Latin verbal root.
Because adsecurare is a term of art in Latin legal sources, it will not appear in English-language case reporters or statutes under this form. Researchers searching Law Mind corpus materials should run parallel searches under the anglicized derivatives: assure, assurance, insure, insurance, surety, and pledge, depending on which branch of the term's usage they are tracing.
Historical Dictionary Support
Burrill is the primary English-language legal dictionary source for this term, and his entry is compact but structurally useful. He correctly identifies both the old English and commercial law senses, providing the Latin definitional gloss — pignore vel fidejussione interposita securum facere — which precisely captures the suretyship meaning. His citation to Spelman and to the charter in Hoveden (anno 1174) grounds the old English usage in a specific documentary tradition, though researchers should treat the Hoveden citation as a pointer to the chronicle tradition rather than a stand-alone authority.
Burrill's cross-reference to adsecuratio (and its alternate form assecuratio) is the more important entry for the commercial law branch. The citation to Loccen's de Jure Maritimo places the insurance sense within the learned maritime law tradition rather than English common law. This is a significant distinction: adsecurare in the insurance sense entered English legal thought through civilian and mercantile channels, not through the common law writ system.
No other historical legal dictionaries in the Law Mind shelf independently develop this term. Jacob's Law Dictionary, Tomlin's, and Bouvier's American law dictionaries — where they treat insurance and suretyship — do so under the anglicized terms, not under the Latin root. This means Burrill is effectively the terminus for Latin-form dictionary treatment in the English legal lexicon.
Jurisdictional Note
As a Latin term of art, adsecurare has no jurisdiction-specific modern application in common law systems. Its relevance is historical and comparative. Researchers working in civil law jurisdictions or in the history of maritime law may encounter assecuratio and cognate terms in Dutch, Italian, and German legal sources where the civilian tradition persisted longer in formal legal writing.