Definition
De modo decimandi (Latin: "of a modus of tithing") is a term from English ecclesiastical law describing a prescriptive right to pay tithes in a special or customary manner, differing from the standard method of rendering one-tenth of produce or income to the church. A claim de modo decimandi arose when a person or landowner asserted, by long custom or prescription, an entitlement to substitute an alternative payment — typically a fixed sum of money, a specific quantity of a particular commodity, or some other defined render — in place of the ordinary tithe in kind. The modus thus modified, without extinguishing, the underlying tithe obligation.
The term is closely associated with the broader doctrine of modus decimandi, which is the substantive right itself; de modo decimandi denotes the procedural or descriptive framing of such a claim, particularly as it appeared in pleadings and jurisdictional disputes between ecclesiastical and common-law courts.
Common Confusion
De modo decimandi is frequently encountered alongside two related but distinct concepts. A modus decimandi is the underlying prescriptive arrangement — the thing itself. De modo decimandi is the descriptive or pleading formula applied to a claim asserting such an arrangement. Separately, a claim de jure decimandi asserts the basic right to receive tithes at all, without any modification; de modo decimandi presupposes that the right to tithe exists and addresses only its form. Researchers encountering either phrase in historical pleadings should be careful not to conflate the existence of a tithe right with the existence of a customary modification to it.
Why It Matters in Research
This term belongs almost entirely to the world of pre-modern English ecclesiastical law and will appear in sources concentrated in the sixteenth through nineteenth centuries, tapering sharply after the Tithe Commutation Act 1836 converted most tithes in England and Wales to fixed rent charges, and then again after the Tithe Act 1936 effectively abolished the tithe system. Researchers encountering de modo decimandi in corpus sources should treat it as a chronological marker: its presence signals a document dealing with ecclesiastical property, church revenue, or jurisdictional competition between church courts and common-law courts.
A critical research trap: because tithe disputes were adjudicated in both ecclesiastical courts and, via prohibition, in the common-law courts of King's Bench and Common Pleas, the same underlying modus claim could generate documents in completely different court record series. A researcher tracing a de modo decimandi dispute should not confine searches to ecclesiastical records alone.
The pleading and proof requirements for a modus were strict at common law. A modus had to be certain, reasonable, and immemorial — requirements that generated a substantial body of case law and treatise commentary. The entries in Blackstone (2 Bl. Comm. 29) and Stephens' Commentaries (3 Steph. Comm. 130) are the standard points of entry and are the sources all four historical dictionaries in this corpus ultimately cite. Rapalje & Lawrence redirect the reader to the headword MODUS rather than defining the term independently, which is itself useful navigational intelligence: the substantive doctrine lives under MODUS in most reference works of that era, while de modo decimandi appears mainly in procedural and pleading contexts.
After the Tithe Commutation Act 1836, claims framed in classical de modo decimandi terms largely ceased, but disputes over the commuted rent charges and the valuation underlying them continued. Researchers should not assume that the disappearance of the Latin formula means the underlying property disputes also ended.
Historical Dictionary Support
All four source dictionaries converge on a single, narrow definition: de modo decimandi is the formula for a claim asserting a special prescriptive manner of tithing in English ecclesiastical law. Black's (both editions) and Burrill share nearly identical language and cite the same two authorities — 2 Bl. Comm. 29 and 3 Steph. Comm. 130. This unanimity reflects the term's settled, technical character; there was no meaningful doctrinal debate about what the phrase meant, only about whether a particular modus met the substantive requirements for validity.
Rapalje & Lawrence's cross-reference to MODUS is the only structural variation among the four entries and is editorially sound: the doctrine is richer under that heading. Researchers who find de modo decimandi in an index or digest and then fail to follow through to MODUS will miss the bulk of the relevant law.
None of the historical dictionaries address the post-1836 landscape or the eventual statutory abolition of tithes. This is an expected gap: legal dictionaries of the nineteenth century described law as it then stood and did not project forward. Researchers should supplement dictionary sources with the text of the Tithe Commutation Act 1836 and the Tithe Act 1936 when tracing the doctrine to its end.
Jurisdictional Note
De modo decimandi is a term of English ecclesiastical law with no direct equivalent in American law. The established church tithe system was never transplanted to the American colonies in operative form, and tithe-based property rights did not become part of American common law. Researchers working in American sources who encounter the phrase are likely reading an English authority cited for analogical or historical purposes only.