Magister officiorum

The magister officiorum (Latin literally for "Master of Offices", in Greek: μάγιστρος τῶν ὀφφικίων, magistros tōn offikiōn) was one of the most senior administrative officials in the late Roman Empire and the early centuries of the Byzantine Empire. In Byzantium, the office was eventually transformed into a senior honorary rank, until it disappeared in the 12th century.

Although some scholars have supported its creation under Emperor Diocletian (r. 284–305), the office can first be definitely traced to the rule of Roman emperor Constantine I (r. 306–337), in 320. Constantine probably created it in an effort to limit the power of the praetorian prefect (praefectus praetorio), until then the Roman emperor's chief administrative aide. The magister supervised the palatine secretariat, divided into four bureaux, the sacra scrinia, each under a respective magister: the scrinium memoriae, the scrinium epistularum, the scrinium libellorum and the scrinium epistolarum Graecarum. The first bureau handled imperial decisions called annotationes, because they were notes made by the emperor on documents presented to him, and also handled replies to petitions to the emperor. The second handled correspondence with foreign potentates and with the provincial administration and the cities, the third dealt with appeals from lower courts and petitions from those involved in them, and the fourth handled the documents issued in Greek and the translation of Latin documents into Greek. Another important duty transferred to the office by Constantine was the supervision of the agentes in rebus, a corps of trusted messengers who also functioned as controllers of the imperial administration. Especially this control of the feared agentes, or magistriani, as they were colloquially known, gave the office great power. The office rose quickly in importance: initially ranked as a tribunus, by the end of Constantine's reign the magister was a full comes.

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