Definition
The solidus legalis is a historical monetary denomination of English law, fixed at a value of 13 shillings and 4 pence in the standard currency of the period in which the term appears in legal texts. It functioned primarily as a money of account — a unit used to express value, calculate debts, fines, and fees, and record transactions — rather than necessarily referring to a coin physically in circulation at that value. The term appears in older English legal instruments, fee schedules, and statutory texts where precise monetary denominations carried legal consequence.
Common Confusion
Two overlapping concepts require separation. First, the solidus legalis as an English legal denomination (13s. 4d.) is distinct from the solidus as a gold coin of the Byzantine Empire, from which the term descended. The English legal usage had largely shed any connection to Byzantine coinage by the medieval period. Second, the solidus legalis should not be conflated with the mark, another common medieval money of account, which was fixed at 13s. 4d. as well — making the two functionally equivalent in value, though terminologically distinct. Researchers encountering either term in the same document should not assume they refer to different amounts; both resolve to 13s. 4d. Third, the solidus in Roman and Byzantine contexts was a gold coin of a specific weight standard; the solidus legalis in English legal usage was not necessarily tied to that physical specification and often operated purely as an accounting unit.
Why It Matters in Research
Researchers working in medieval and early modern English legal records — fee tables, amercements, writs, plea rolls, conveyancing instruments — will encounter monetary values expressed in archaic units whose purchasing power and legal significance are easily misread. The solidus legalis at 13s. 4d. is one such unit, and its equivalence to the mark is a practical trap: a document stating a penalty in solidi and another stating it in marks may be imposing identical obligations, but superficial reading suggests different terms. Failure to recognize this equivalence can distort analysis of fine schedules, bond amounts, and contractual obligations in historical sources.
The term's frequency declines sharply after the early modern period. By the time of later English legal consolidation, explicit monetary references shifted toward pounds sterling with less reliance on intermediate units of account like the solidus legalis. Researchers using the Law Mind corpus should expect the term to appear almost exclusively in pre-18th-century materials, glossed texts, or scholarly commentary on earlier instruments. Its presence in a document can itself serve as a rough dating signal.
The connection between solidus and shilling — suggested in the supplemental Black's entry — is also relevant for researchers tracing the linguistic and conceptual lineage of English monetary law. The abbreviation "s." for shilling derives from solidus, a connection that persists in British monetary notation through decimalization in 1971.
Historical Dictionary Support
Black's Law Dictionary in both its primary and supplemental editions defines the solidus legalis by its fixed value of 13s. 4d., citing Stephens' Commentaries (4 Steph. Comm. 119n.) as authority. The two editions are substantively consistent on this valuation. The supplemental edition adds the important historical dimension: the solidus originated as a gold coin of the Byzantine Empire before the term migrated into medieval European usage as a flexible label applied to various coins or money-of-account designations. The supplemental edition also explicitly identifies the solidus as the probable etymological root of "shilling."
What neither edition addresses is the functional equivalence of the solidus legalis and the mark at 13s. 4d., which is significant for practical legal research. Neither edition discusses the term's decline in usage or offers guidance on its regional variation within English practice. Historical dictionaries, predictably, treat the entry as a static definition rather than a research navigation tool. Researchers should supplement these entries with reference to glossaries of medieval monetary terminology and scholarship on English monetary history for fuller context.
Jurisdictional Note
The solidus legalis is a term of English legal history and has no operative significance in modern common law jurisdictions. Its relevance is confined to the interpretation of historical English instruments, records, and statutes. Researchers working in Scottish, Irish, or continental European legal archives should exercise caution, as parallel terms in those traditions may carry different valuations or referents.