Definition
A writ of medieval English law directed to those who had imposed a bailiwick or other secular office upon a person in holy orders, commanding them to release that person from the obligation. The writ recognized that clergy were subject to canon law and ecclesiastical jurisdiction, and that compelling a clerk in orders to serve in a secular administrative capacity conflicted with the privileges and duties of clerical status. It was a remedy available to the cleric himself, or on his behalf, to secure discharge from an office improperly thrust upon him.
Common Confusion
Do in officium is closely related to, and should be read alongside, the writ Clerico infra sacros ordines constituto non eligendo in ballium (referenced in Black's as "CLERICO INTRA SACROS, etc."). Both writs protect clergy from secular burdens, but they address different moments: the Clerico writ operated to prevent a cleric from being compelled to serve as a surety or bail; do in officium addressed the specific problem of an office already imposed. Researchers encountering either writ in historical records should not assume they are interchangeable — each had its own procedural posture and target.
Why It Matters in Research
This is a highly specialized writ of the medieval English common law, obsolete in modern practice and relevant almost exclusively to researchers working in ecclesiastical history, early English administrative history, or the development of clerical privilege as a legal doctrine. Several navigational points matter:
First, the writ presupposes the medieval distinction between secular and ecclesiastical persons — a distinction with significant jurisdictional consequences in pre-Reformation England. Researchers tracing the boundary between royal and church authority will find this writ among a cluster of remedies designed to preserve clerical exemptions from secular administration.
Second, the primary reference in both historical dictionaries is Reg. Orig. 143 — the Registrum Omnium Brevium, a register of writs used by English practitioners. Researchers should understand that citations to "Reg. Orig." refer to this register, which exists in multiple printed editions from the sixteenth and seventeenth centuries. The folio numbering may vary across editions.
Third, do in officium appears in sources that also discuss the term clericus, which had at least two distinct meanings depending on context: in civil law, any person in holy orders (monk or priest); in old English law, more narrowly a secular priest, or a court clerk issuing writs, or a household officer managing finances. Rapalje & Lawrence flags this ambiguity directly. When reading historical materials that use clericus in connection with this writ, the civil-law sense is almost certainly intended.
Fourth, this writ has no modern analog and no significant jurisdictional variation to track — it is a historical artifact, not a living doctrine. Researchers should treat it as a terminus in the development of clerical privilege, not a starting point for any contemporary legal argument.
Historical Dictionary Support
Black's Law Dictionary and Rapalje & Lawrence are in complete agreement on the definition, and both cite Reg. Orig. 143 as the authoritative source — suggesting neither is drawing on independent research beyond the register itself. The entries are nearly verbatim identical, which is characteristic of nineteenth-century legal dictionaries that drew heavily on shared sources.
What the historical dictionaries do not supply is any substantive discussion of how the writ functioned procedurally, who had standing to seek it, or how frequently it was used in practice. The entries are definitional placeholders, not analytical treatments. Researchers seeking the writ in its operational context will need to look beyond the dictionaries to the register itself and to secondary scholarship on English ecclesiastical law and the history of clerical privilege.
Neither dictionary connects do in officium to the broader framework of benefit of clergy or to the gradual erosion of clerical exemptions under Tudor legislation — a gap that a researcher tracing the arc of ecclesiastical privilege would need to fill from other sources.