Definition
Compositio Ulnarum et Perticarum (Latin: "the composition of ells and perches") is the title of a medieval English statute establishing standardized units of linear measure — specifically the ell and the perch — for use throughout the realm. The statute was part of a broader effort by the English crown to impose uniform weights and measures across a territory where local variation was widespread and commercially disruptive. It belongs to a cluster of early medieval enactments concerned with metrology, trade regulation, and the suppression of fraudulent measure.
The ell was a unit used principally for measuring cloth, approximately 45 inches in English usage. The perch (also rod or pole) was a unit of land measure, standardized at 16½ feet and foundational to surveying and the measurement of agricultural holdings.
Common Confusion
The title is frequently grouped with two closely related enactments: the Assisa de Mensuris (Assize of Measures) and the Compositio Mensurarum (Composition of Measures). These instruments overlap in subject matter and era, and historical sources do not always distinguish them clearly. Researchers should not assume that a reference to one of these instruments excludes the others or that their provisions were mutually exclusive. They collectively form the medieval English framework for standardized measure and are often discussed as a unit in secondary literature, even though they were technically distinct enactments.
Why It Matters in Research
This term will appear in Law Mind corpus sources almost exclusively in one of two contexts: (1) historical treatments of English weights-and-measures law, or (2) citations by commentators — Blackstone chief among them — situating early statutory history within the development of royal prerogative and parliamentary authority.
Blackstone's citation (1 Bl. Comm. 275) is the primary transmission point for modern researchers encountering this title. Because Blackstone cites it in passing as an example of early parliamentary enactment, researchers focused on constitutional history rather than commercial or trade law may encounter the term without context for its substantive content.
Key research traps:
The dating and provenance of the statute are uncertain. Medieval metrology statutes were often promulgated without precise dating, attributed to reigns rather than regnal years, and later confirmed or re-enacted under different names. A source citing this statute may be referring to an original enactment, a confirmation, or a later compilation of earlier customary rules given statutory form.
Latin titular variations are common. "Perticarum" may appear as "Percharum" or in Anglicized form as "perches" in later reprints. Search strategies should account for both Latin and vernacular forms.
The statute has no living legal significance. It is of purely historical interest. Any corpus source discussing it is engaged in legal history, not operative law.
Researchers working on the history of English commercial regulation, the Statute of Measures, or the broader Assize tradition will find this instrument relevant as a predecessor to later, better-documented enactments.
Historical Dictionary Support
Black's Law Dictionary (2nd Ed., Supplemental) provides the entry in full: "The statute of ells and perches. The title of an English statute establishing a standard of measures. 1 Bl. Comm. 275." The entry is accurate as far as it goes but offers little beyond a translation of the Latin title and a pointer to Blackstone. It does not date the statute, identify its chapter or session, or distinguish it from related measures instruments.
What the historical dictionaries miss: No entry surveyed provides the substantive content of the statute, its relationship to the broader Assize tradition, or the practical commercial context in which it operated. Researchers seeking more than the label must move beyond the legal dictionaries to legal historians of medieval English trade and metrology.
Jurisdictional Note
This statute is exclusively English in origin and application. It has no Scottish, Irish, or colonial analog under this title. References to it in American legal sources are purely historical or academic.