History and functions
Late Roman Empire
Although some scholars have supported its creation under Emperor
Diocletian (r. 284–305), the office can first be definitely traced to the rule of
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
The office's powers were further enhanced in 395, when Emperor
Arcadius (r. 395–408) removed the purview of the Public Post (
Greek: δημόσιος δρόμος), the palace guard (
Scholae Palatinae) and the imperial arsenals (fabricae) from the
praetorian prefecture and handed them to the magister officiorum.
 These last changes are reflected in the
Notitia Dignitatum, a list of all offices compiled circa 400.
 Sometime in the 5th century, the Eastern magister also assumed authority over the border guards or
In the course of time, the office also took over the coordination of foreign affairs (already in the late 4th century, the official
interpreters were under the control of the magister officiorum for this reason), and in the East, the Notitia records the presence of four secretaries in charge of the so-called
Bureau of Barbarians under the magister's supervision.
 One of the most important incumbents of this office was
Peter the Patrician, who held the position from 539 to 565 and undertook numerous diplomatic missions in this role for Emperor
Justinian I (r. 527–565). The office was also retained in
Ostrogothic Italy after the fall of the
Western Roman Empire, and was held by eminent
Roman senators such as
The office survived as a bureaucratic function in the eastern (or
Byzantine) half of the Roman Empire, but during the late 7th or the 8th century, most of the office's administrative functions were removed, and it was converted into the dignity of magistros (Greek: μάγιστρος, female form magistrissa, μαγίστρισσα).
 At least until the time of Emperor
Leo VI the Wise (r. 886–912), however, the full former title was remembered: his powerful father-in-law,
Stylianos Zaoutzes, is recorded once again as "master of the divine offices" (μάγιστρος τῶν θείων ὀφφικίων).
 In his administrative functions, the magister officiorum was replaced chiefly by the
logothetēs tou dromou, who supervised the Public Post and foreign affairs,
 while the imperial bodyguard was transformed into the
Until the reign of Emperor
Michael III (r. 842–867) there seem to have been only two magistroi, the senior of whom was termed prōtomagistros (πρωτομάγιστρος, "first magistros"), and who was again one of the senior ministers of the state (without specific functions) and head of the
Byzantine Senate. From the reign of Michael III on, the title was conferred on more holders, effectively becoming a court rank, the highest in the
Byzantine hierarchy until the introduction of the
proedros in the mid-10th century.
 The List of Precedence (
Klētorologion) of Philotheos, written in 899, implies the existence of 12 magistroi, while during the reign of Emperor
Nikephoros II Phokas (r. 963–969), the western envoy
Liutprand of Cremona recorded the presence of 24.
 The rank continued in existence thereafter, but lost increasingly in importance. In the late 10th and 11th centuries, it was often held in combination with the title of
vestēs. From the late 11th century it was considerably devalued, especially in the
Komnenian period, and disappeared entirely by the mid-12th century.