Definition
A medieval legal term, likely a corruption of *laganum maris* (Latin: "lagan of the sea"), referring to the right by which goods cast overboard from a vessel in distress became the property of the Crown or the lord upon whose shores they were stranded. The term belongs to the same family of maritime salvage doctrines as jetsam and flotsam, and represents an early common-law mechanism for asserting sovereign or seignorial control over goods lost or abandoned at sea.
The term has no independent modern legal currency. It survives only as a historical artifact in legal dictionaries and treatises on maritime law and royal prerogative.
Common Confusion
ALGARUM MARIS is closely associated with — and likely a variant corruption of — LAGAN (also spelled *ligan*), which itself is often confused with FLOTSAM and JETSAM. The distinctions matter for historical research:
- **Flotsam**: goods found floating on the sea after a shipwreck, without having been deliberately thrown overboard.
- **Jetsam**: goods deliberately cast overboard (*jettisoned*) to lighten a vessel in distress, which sink and remain on the seabed.
- **Lagan**: goods cast overboard and marked with a buoy so the owner may recover them, or more loosely, goods that sink to the bottom without such marking.
Algarum maris appears to collapse the lagan concept into a royal prerogative claim, but historical sources are not fully consistent in how they distinguish these categories. Researchers should not assume that period sources use these terms with modern precision.
Why It Matters in Research
This term is almost exclusively encountered in historical legal dictionaries and treatises on royal prerogative, admiralty, and maritime custom. It has no operative presence in modern statutes or case law. A researcher encountering it in a primary source — a medieval roll, a treatise on the law of the sea, or a plea asserting Crown rights over wrecked cargo — should treat it as a local or period variant for lagan rights rather than a term of art with settled independent meaning.
The corruption theory advanced by both editions of Black's is significant: it signals that even contemporaneous legal sources may have used the term imprecisely or interchangeably with related concepts. This creates a trap for researchers conducting keyword searches in historical corpora. A document that uses *algarum maris* may be addressing lagan, jetsam, wreck of the sea, or some overlapping combination depending on the drafter's jurisdiction, period, and sources.
The royal prerogative over wreck and stranded goods was contested terrain in English legal history, with lords claiming competing rights based on local custom and charter grants. Where a document invokes algarum maris, the researcher should investigate whether the underlying claim is a Crown prerogative, a franchised right held by a lord, or a contested entitlement — the term alone does not settle that question.
No significant case law develops around this specific term. Its doctrinal content is absorbed by the broader history of wreck, lagan, and admiralty jurisdiction.
Historical Dictionary Support
Both editions of Black's Law Dictionary treat algarum maris identically in substance, differing only in minor typographical artifacts of the printing. Both cite Spelman, Jacob, and Du Cange as their authorities — Spelman's *Glossarium* and Jacob's *Law Dictionary* being standard reference points for archaic English legal terms, and Du Cange's *Glossarium Mediae et Infimae Latinitatis* for medieval Latin usage. Neither edition ventures beyond the corruption theory or provides a definitive independent definition, which itself confirms that the term was obscure even at the time of compilation.
Notably, neither edition attempts to reconcile the term with the then-current English law of wreck and salvage or to situate it within admiralty jurisdiction. Historical dictionaries treat it as a curiosity of medieval prerogative doctrine rather than a living term. Researchers should not expect further elaboration from other period sources; the citations to Spelman, Jacob, and Du Cange represent the practical limit of the historical record on this term.
Jurisdictional Note
The term originates in English medieval law and reflects the structure of English feudal tenure over coastal lands. Analogous doctrines existed in continental European maritime customs, but algarum maris as a term appears specifically in the English common-law dictionary tradition. It has no established presence in American law.