Definition
A concordat is a formal agreement or compact between two sovereign parties. The term carries three related but distinct meanings in legal usage:
1. International law: A compact or convention between two or more independent governments, functionally equivalent to a treaty. Usage in this sense is uncommon in modern practice, where "treaty" or "convention" is preferred.
2. Canon and ecclesiastical law (primary modern usage): An agreement between the Holy See (the papacy) and a temporal sovereign or national government, regulating ecclesiastical matters of mutual concern — such as the appointment of bishops, the legal status of the Catholic Church within the state, education, marriage law, or church property. This is the sense in which "concordat" is most widely used today and throughout history.
3. French and civil law: A compromise arrangement between an insolvent debtor and creditors, by which the debtor agrees to pay a specified proportion of outstanding debts within a defined period, and in exchange the creditors discharge the remainder. Functionally analogous to a composition in bankruptcy under common law systems.
Common Language
Modern common usage (Wiktionary): A formal agreement between two parties, especially between a church and a state; specifically, an agreement between the Pope and a government.
Historical common usage (Webster's 1913): A compact, covenant, or agreement concerning anything; most specifically, an agreement made between the pope and a sovereign or government for the regulation of ecclesiastical matters with which both are concerned.
The gap between common and legal usage is narrow but worth noting. Ordinary usage has largely absorbed the ecclesiastical-diplomatic sense, treating "concordat" as a near-synonym for a church-state agreement with the Vatican. Legal usage is broader: the term historically extended to inter-sovereign compacts generally and, in civil law systems, to creditor-debtor compositions. Researchers encountering "concordat" in French or Spanish legal sources should not assume an ecclesiastical context.
Common Confusion
Concordat is sometimes used interchangeably with "treaty" or "convention" in older sources, but the terms are not synonymous. A treaty is the general instrument of international agreement; concordat is a specialized term, most properly reserved for agreements involving the Holy See or, in civil law, for debtor-creditor compositions. Confusing concordat with "compact" is also common in historical texts — both terms signal a bilateral agreement, but "compact" carries broader application and no ecclesiastical connotation.
The Black's 2nd edition entry in the source material contains text relating to "conclusion" and estoppel rather than concordat — an apparent editorial mismatch. Researchers using that edition should verify the relevant entry independently.
Why It Matters in Research
The term's meaning shifts sharply depending on the legal tradition and subject matter of the source. A researcher in ecclesiastical or canon law history will encounter "concordat" almost exclusively in the church-state sense. A researcher in French civil law or bankruptcy history will encounter it in the creditor-composition sense. A researcher in general public international law from the 18th or 19th century may find it used as a generic synonym for treaty.
The ecclesiastical usage has the longest and most documented history. Concordats between the papacy and European states date to the medieval period and continue into the present; the Lateran Treaty of 1929 between the Holy See and Italy is among the most studied modern examples. In jurisdictions with strong civil law traditions (France, Spain, Latin America), the bankruptcy composition meaning appears in 19th-century commercial codes and should not be misread as a religious or diplomatic instrument.
Historical sources predating 1900 frequently use "concordat" without specifying which sense is intended, relying on context. Researchers should anchor meaning to the subject matter of the surrounding text before cross-referencing related entries.
Historical Dictionary Support
The historical dictionaries present consistent but partial coverage. Black's (1st ed.) captures all three meanings explicitly — international compact, papal agreement, and French bankruptcy composition — making it the most complete of the shelf sources for this term. Bouvier confines the definition to inter-sovereign agreements and papal compacts, omitting the bankruptcy sense entirely. Burrill draws only on the ecclesiastical meaning, citing Webster, and adds nothing beyond that. Black's 2nd edition contains an apparent textual error in the source material (the entry as supplied discusses "conclusion" and estoppel, not concordat), and should be verified against a reliable copy.
The shelf sources agree on the papal-temporal agreement as the term's primary legal meaning. None of the historical dictionaries develops the constitutional or separation-of-powers dimensions that make concordats significant in modern comparative constitutional law — a gap that matters for researchers approaching the subject from a church-state or human rights angle.
Jurisdictional Note
In common law jurisdictions (United States, United Kingdom, Australia), the term "concordat" has no domestic legal force as a term of art; it appears mainly in historical, ecclesiastical, or international law contexts. In civil law jurisdictions, particularly France, the creditor-composition meaning had statutory grounding in 19th-century commercial codes, though modern insolvency law has largely replaced it with different terminology. The Holy See's concordats are treated as binding international agreements under public international law regardless of the domestic legal tradition of the contracting state.