Definition
A writ directed to a mayor or similar municipal official who had been commanded by royal writ to deliver seisin of lands to the king's grantee but had delayed or failed to do so. The writ required the official to show cause — to explain to the court why he had not performed his duty. The phrase is Latin for "that you signify to us the cause why," which captures the writ's essential demand: an account of the delay.
Why It Matters in Research
This is an obscure procedural writ of the medieval English royal administration and will appear almost exclusively in early English legal records, Year Books, and treatises on real property procedure. Researchers encountering this term are almost certainly working in pre-modern English legal history, particularly in contexts involving crown grants of land and the administrative machinery through which royal conveyances were executed.
Several research traps are worth noting. First, the writ belongs to a cluster of writs governing seisin — the formal possession of land — and cannot be understood without familiarity with that concept and with the role of the mayor or sheriff as the crown's instrument for delivery of possession. Second, the writ presupposes an earlier royal command that had gone unexecuted; it is not a primary instrument but a secondary one triggered by non-compliance. Researchers should look for the antecedent writ in any documentary sequence. Third, Black's Supplemental entry is brief and derivative, citing only Blount and Cowell — both seventeenth-century English legal lexicographers. Neither source reflects modern scholarship on medieval land administration, and neither situates the writ within the broader system of real actions. Researchers should treat the Black's entry as an access point, not a terminus.
This term does not appear in standard modern legal research and has no live procedural counterpart in American or contemporary English law. Its value is entirely historical.
Historical Dictionary Support
Black's 2nd Edition Supplemental entry is the only dictionary source available here, and it is itself derivative, tracing directly to Thomas Blount's Nomo-Lexicon (1670) and John Cowell's The Interpreter (1607). Both Blount and Cowell were English legal antiquarians compiling glossaries of terms already falling out of active use in their own time, which means the writ was archaic even by the seventeenth century. Black's adds nothing beyond what those sources supply.
The entry captures the essential function accurately: this was a mandamus-type instrument within the royal land administration system, compelling an official to act or explain his inaction. What the historical sources do not address is the procedural context — when the writ issued, what court superintended it, how it related to writs of novel disseisin or other real actions, and what remedies followed from a sufficient or insufficient showing of cause. For that level of detail, researchers must go beyond the lexicographic tradition entirely and into the primary records of the English chancery and common law courts.
Jurisdictional Note
This writ is exclusively a creature of medieval and early modern English law. It has no American equivalent and was not received into the law of any American jurisdiction. Its relevance today is confined to legal history and the interpretation of historical English documents.