Who was a Magister militum in the Roman Empire?

The title “magister militum” in the Roman Empire can be translated as “Master of the Soldiers.” It was a senior military rank established in the later stages of the Roman Empire, particularly during its transition from the Principate to the Dominate periods.

Role and Responsibilities

A magister militum was, essentially, a high-ranking general. He had authority over significant portions of the Roman army, and in some cases, this power could extend to entire frontiers or even multiple regions.

Given the military nature of the late Roman state, the magister militum also played a key role in the imperial court. They often functioned as close advisors to the emperor on military and sometimes even on political matters.

At times, a magister militum might also take on diplomatic responsibilities, especially in areas where military and foreign policy intersected.


  1. Magister Peditum: Master of Foot, essentially meaning the commander of the infantry forces.
  2. Magister Equitum: Master of Horse, the commander of cavalry forces.

As the empire grew more complex and the threats more multifaceted, these roles further evolved. By the time of the Late Roman Empire, there were several magistri militum in different parts of the empire, often with regional responsibilities.


Given the tumultuous nature of the Late Roman Empire, with its frequent external threats and internal upheavals, the position of magister militum became increasingly influential. Some magistri militum exerted significant power behind the scenes, and there were instances where they could make or break emperors. Stilicho, Ricimer, and Aetius are examples of magistri militum who wielded immense influence during their lifetimes.

In many ways, the rise of such powerful military figures can be seen as indicative of the broader transformations and challenges facing the Roman Empire in its later stages.

Territorial level appointments

Under the reign of the successors of Emperor Constantine, the organizational structure of the Roman military underwent further refinements. The titles of “magister peditum” (master of foot) and “magister equitum” (master of horse) were no longer just top military ranks; they also began to represent territorial jurisdictions.

For every praetorian prefecture, specific individuals were appointed as magistri peditum and magistri equitum. Praetorian prefectures were administrative regions of the Roman Empire, and these included areas like Gallias (Gaul), Italiam (Italy), Illyricum, and Orientem (the East).

Additionally, separate appointments were made for the regions of Thrace and sometimes Africa. These appointments meant that each of these territories had its own chief infantry and cavalry commanders, responsible for the military affairs of that specific region.

However, practicalities and the needs of the empire sometimes dictated that a single individual would be entrusted with the responsibilities of both roles. In such cases, they were given the combined title of “magister equitum et peditum” or “magister utriusque militiae,” which means “master of both forces.” This title indicated their authority over both the infantry and the cavalry of that region, consolidating military command and ensuring a more unified approach to defense and military campaigns.

While some magistri were stationed regionally, others remained closer to the seat of imperial power and were “in praesenti” (in the presence) of the emperor. These magistri “in praesenti” served at the emperor’s immediate disposal and were ready to act on direct imperial orders.

By the end of the 4th century, there was a shift in nomenclature. The distinction between magistri peditum and magistri equitum became less pronounced, and regional commanders were more commonly referred to by the general title “magister militum,” which translates to “master of the military.” This simplification reflected their broad authority over all military aspects in their designated regions, be it infantry, cavalry, or other forces.

Magistri militum compared with the Roman Emperor

The term “magister militum” referred to the senior military officer of the Roman Empire, essentially acting as the highest-ranking general beneath the emperor, who remained the ultimate military authority.

This role can be likened to a modern-day war theatre commander, responsible for overseeing vast military operations, directing troops, and strategizing against enemy forces in a specific region or across several regions.

However, while they held significant military power, ultimate strategic decisions and broad imperial directives were still within the purview of the emperor. The magister militum was a central figure in the empire’s defense and often played crucial roles in both military campaigns and political affairs.

The role in the Western Roman Empire

In the Western Roman Empire, the complexities and pressures of governing a vast territory led to the evolution of a central military leadership position known as the “magister utriusque militiae,” often abbreviated as MVM. This title, which translates to “master of both forces,” signified the immense military authority vested in a single individual, overseeing both the infantry (pedes) and the cavalry (equites).

The holder of this office wielded significant power, often surpassing that of other military and civil officials. Because of this, the magister utriusque militiae frequently became the real force driving the politics of the empire, acting as the de facto ruler or the key influencer behind the emperor.

Notable figures like Stilicho, Flavius Aetius, and Ricimer occupied this role and played pivotal parts in the history of the late Western Roman Empire. Their influence was often so pronounced that they could make or break emperors, making the title of MVM one of the most influential in the Western Roman hierarchy.

Role in the Eastern Roman Empire

In contrast, the Eastern Roman Empire (often referred to as the Byzantine Empire in its later phases) had a somewhat different arrangement. Instead of consolidating power under a single commander-in-chief, the East had two senior generals.

Both were designated as “magister militum praesentalis.” This title can be translated to “master of the soldiers in the presence [of the emperor],” indicating their proximity and allegiance to the emperor.

The existence of two such positions in the East was likely a measure to balance and distribute military power, preventing any one individual from amassing the kind of authority that their western counterparts often did.

The role during the reign of Justinian the Great

During the time of Emperor Justinian I, the Eastern Roman Empire faced heightened military challenges and also saw territorial expansion. To effectively manage these new territories and threats, Justinian introduced new military roles:

  1. Magister militum per Armeniam: This position oversaw the Armenian and Caucasian regions, which previously were under the purview of the magister militum per Orientem.
  2. Magister militum per Africam: Following the reconquest of North African provinces around 534 AD, this post was established. An underling, the magister peditum, was also introduced to assist in military leadership here.
  3. Magister militum Spaniae: This role, created circa 562, was meant to administer the Spanish territories.

6th century AD onward

The 6th century saw both internal and external pressures. Given these crises, there was often a need to merge the top regional civil role with the magister militum office for more efficient administration. By 584, this blending of roles was institutionalized with the establishment of exarchates in Ravenna and Carthage. These exarchates combined both military and civil authority.

Following the loss of eastern provinces to Muslim forces in the 640s, the remaining field armies and their leaders became the foundation of the “themata” system — a new provincial arrangement in the Byzantine Empire.

Interestingly, the title of “magister militum” wasn’t confined just to the Byzantine world. In early medieval Italy, regions like the Papal States and even Venice had supreme military commanders using this title. Venice’s Doge, in particular, saw himself as a successor to the Exarch of Ravenna, symbolizing the continuation of Roman traditions.

Famous magistri militum

Several “magistri militum” (masters of the soldiers) rose to prominence during the Late Roman Empire, wielding considerable power, influence, and, in some cases, effectively controlling the fate of emperors. Here are some of the most famous:


A half-Vandal general who served under the Western Roman Emperor Honorius. Stilicho defended Italy against various barbarian invasions and became one of the most powerful figures in the Western Roman Empire. He is perhaps best known for his defense against the Gothic king Alaric and his efforts to preserve the empire from numerous threats.

Germanic-Roman general (magister militum) Stilicho with his wife Serena and his son Eucherius. Copy of an ivory carving. The original dyptich, carved circa 395, is in Monza (Italy).

Flavius Aetius

Often called the “Last of the Romans,” Aetius was a magister militum who played a pivotal role in holding together the crumbling Western Roman Empire in the 5th century. He’s most famous for uniting with the Visigoths to defeat Attila the Hun at the Battle of the Catalaunian Plains in 451 AD.


A barbarian-born general who became a key power player in the mid-5th century Western Roman Empire. While he never took the title of emperor himself, Ricimer effectively ruled the empire behind the scenes by setting up and deposing puppet emperors.

Flavius Ardabur Aspar

An Alan serving the Eastern Roman Empire, Aspar had significant influence during the reigns of several Eastern Roman emperors. Like Ricimer in the West, Aspar was a kingmaker, playing a role in elevating Leo I to the throne. However, his power was curtailed when Leo I asserted his independence and eventually had Aspar executed.


While he held various military titles during his career, Belisarius, under Emperor Justinian I of the Byzantine Empire (Eastern Roman Empire), is often remembered as one of the most brilliant generals of antiquity. He played a central role in Justinian’s reconquest campaigns, reclaiming parts of the former Western Roman Empire, including Carthage and Rome.


Another prominent general under Justinian I, Narses was instrumental in ending the Gothic War in Italy. He is best remembered for his victory against the Ostrogoths at the Battle of Taginae and his role in the defeat of the Franks and Alamanni at the Battle of Casilinum.

These figures, among others, were not just military leaders but also significant political actors in the complex arena of Late Roman/Early Byzantine politics and power struggles.

Questions & Answers

How and when was the rank created?

The title “magister militum” emerged in the Roman Empire during the 4th century as a result of significant administrative and military reforms initiated by Emperor Constantine the Great.

Prior to this change, the praetorian prefects, primarily administrative officers, held military responsibilities. However, Constantine sought to separate and specialize these roles, leading to the establishment of distinct military posts.

Two primary roles were established under this reformation

  1. Magister Peditum: This title translates to “master of foot,” and the holder of this title was in charge of the infantry, essentially overseeing the foot soldiers of the empire.
  2. Magister Equitum: Translating to “master of horse,” this title was more prestigious and was given to the officer overseeing the empire’s cavalry. It’s worth noting that the title “magister equitum” wasn’t new; it dated back to the Roman Republic, where the magister equitum acted as the deputy to a Roman dictator, providing a balance of power.

Over time, as the empire’s challenges grew, these roles evolved and sometimes merged, with some officers even holding both titles, reflecting the complexity and fluidity of Roman military organization in this period.

What would the rank be equivalent in today’s term?

The title “magister militum” in the Roman and Byzantine eras can be somewhat difficult to translate directly into modern military ranks due to differences in military structures, responsibilities, and historical contexts. However, if we were to make a comparison:

The “magister militum” would be somewhat equivalent to a Four-Star General or Field Marshal in modern armies. This is based on their responsibilities, which included commanding large sections of the empire’s troops, devising and implementing military strategies, and often playing significant roles in political decisions.

It’s worth noting that the “magister militum” often held more political power than a typical modern general, particularly in the later years of the Western Roman Empire and during the Byzantine era. They would sometimes act as kingmakers, regents, or even as de facto rulers, especially during periods of weak central leadership.

This political dimension doesn’t typically align with the roles of modern military generals, making the “magister militum” a unique blend of military commander and high-ranking statesman.

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