Definition
Magister libellorum is a Latin title meaning "Master of Petitions" or "Master of Requests." It denotes a high administrative office of the Roman Empire responsible for receiving, reviewing, and managing petitions and formal requests addressed to the emperor. The officer holding this title served as a principal intermediary between the imperial administration and those seeking imperial rescripts, decisions, or relief. The magister libellorum drafted or supervised the imperial responses to written petitions (libelli), making the office a significant point of control within the Roman bureaucratic hierarchy.
Common Confusion
Do not conflate the Roman magister libellorum with the English Master of Requests. The English office presided over the Court of Requests, a prerogative court handling small equity matters from the sixteenth century onward, and has no institutional or historical connection to the Roman imperial chancellery. The shared English translation has caused these offices to be conflated in general reference works. In legal history research, context (Roman law versus English equity) should resolve the ambiguity, but researchers should verify which institution a source is discussing before drawing doctrinal conclusions.
Why It Matters in Research
This term appears almost exclusively in historical and Roman law contexts within the Law Mind corpus. Researchers are most likely to encounter it in treatments of Roman civil procedure, imperial administration, and the rescript system — the mechanism by which the emperor responded authoritatively to legal questions submitted by officials, judges, or private litigants. Those rescripts, channeled through the magister libellorum, carried the force of imperial law and fed directly into the Justinianic compilations.
Two navigational points matter. First, the term is a title of office, not a legal doctrine or cause of action — researchers searching for substantive Roman law rules should not expect this term to yield doctrinal content directly. It is an institutional marker pointing toward the rescript system and imperial chancery practice. Second, the translation "Master of Requests" used by both Black's and Bouvier's can create ambiguity for researchers working in parallel on English legal history, where "Master of Requests" refers to an entirely separate office within the English Court of Requests. These are unrelated institutions separated by more than a millennium. A researcher moving between Roman law sources and English equity or prerogative court materials should be alert to this terminological overlap.
The office is also connected to broader Roman administrative terminology — the magister libellorum functioned within a constellation of imperial secretarial offices (scrinia) alongside the magister epistularum (correspondence) and magister a memoria (archives). Understanding where this title sits in that structure clarifies why sources treat it as a high civilian office of considerable juristic influence.
Historical Dictionary Support
Both Black's Law Dictionary and Bouvier's Law Dictionary provide only minimal entries — each offers the translation "Master of Requests" and notes the Roman imperial context, with Black's adding the bare descriptor "a title of office under the Roman Empire." Neither source elaborates on the office's function, its relationship to the rescript system, or its significance within Roman administrative law. The entries read as glossary-level identifications rather than substantive definitions.
This brevity is consistent with the treatment these dictionaries give to most Roman office titles: they confirm the translation and period without engaging the juristic significance. Researchers relying solely on these entries would understand the term as a Roman title but would have no guidance on why it appears in discussions of imperial rescripts or the development of Roman legal sources. The historical dictionaries agree on the translation; neither is wrong. But both leave substantial analytical work to the researcher.