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Proclaiming Claudius Emperor

The Praetorian Guards: To Serve and Protect the Roman Emperors… Most of the Time


The Praetorian Guard is said to be one of the most prestigious military units in the ancient world, and is arguably one of the most well-known today. These elite soldiers are best known for serving as the Roman Emperors’ bodyguards. Ironically, several emperors were actually assassinated by their own Praetorian Guards and a few others were placed on the throne by them. Apart from that, the Praetorian Guard had other duties that are perhaps less well-known than their primary duty of protecting the emperor.

The Origins of the Praetorian Guard

It is said that the origins of the Praetorian Guard can be found in the Roman Republic. During that period of time, they were formed to protect the generals of the Roman army whilst in the field. A Roman general was known as a praetor, and his residence in the field was called the praetorium. Thus, the bodyguards of the praetor were called the Praetorian Guards.

Scholars believe that this unit of bodyguards was first formed by Scipio Africanus, who chose its members from his bravest troops, exempted them from all their duties except guarding his person, and gave them a six-fold pay. Nevertheless, it has been pointed out that the practice of using selected troops as bodyguards can be found in earlier times of the Republic as well.

Scipio’s noble deed. Painting by Nicholas Poussin (1640). Scipio Africanus may have been the first to form the Praetorian Guards.

Scipio’s noble deed. Painting by Nicholas Poussin (1640). Scipio Africanus may have been the first to form the Praetorian Guards. (Public Domain)

Whilst Republican generals had their own personal bodyguards, the establishment of the Praetorian Guard as an institution was only achieved during the reign of Augustus. Due to the turmoil of civil war and social strife, Augustus saw the need to create a body of soldiers that would swear undivided loyalty to his person. Thus, unlike other military units, the Praetorian Guards would only engage in combat or go on campaigns at the direct behest of Augustus.

It is well-known that Augustus sought to maintain some of the values and traditions of the Roman Republic. Thus, initially, the Praetorian Guards stationed within the walls of Rome were not allowed to wear their customary armor. Instead, they wore the civilian toga, and were known as the cohors togata. Although they looked like lictors from the Republican era, they were armed with the standard gladius, rather than the customary fasces (bundled wooden rods) of this office.

Statue of a Praetorian Guard.

Statue of a Praetorian Guard. (Public Domain)

Other Roles of the Praetorian Guards –Spies, Crowd Control, and in the Games

Apart from directly protecting the emperor, the Praetorian Guards protected their patron and his interests indirectly by functioning as a kind of secret police force. It is said that the Praetorian Guards engaged in espionage, intimidation, arrests, and even covert executions of those judged to be a threat to the emperor.

Some Praetorians are said to have disguised themselves as ordinary citizens and attended public spectacles and protests in order to monitor and arrest anyone who criticized the emperor. When not disguised as ordinary citizens at these public events, the Praetorian Guards would be used for crowd control.

Occasionally, the Praetorian Guards would also participate in the games. For example, literary sources mention that they participated in the wild beast hunts to demonstrate their martial prowess. In Suetonius’ The Lives of the Twelve Caesars: The Life of Claudius, for instance:

“In addition to the chariot races he exhibited the game called Troy and also panthers, which were hunted down by a squadron of the praetorian cavalry under the lead of the tribunes and the prefect himself.”

In 52 AD, the Emperor Claudius hosted a staged sea battle (naumachia) on the Fucine Lake, and the Praetorian Guards were involved in that spectacle as well.  According to the Roman historian Tacitus,     

Claudius equipped triremes, quadriremes, and nineteen thousand combatants: the lists he surrounded with rafts, so as to leave no unauthorized points of escape, …. On the rafts were stationed companies and squadrons of the praetorian cohorts, covered by a breastwork from which to operate their catapults and ballistae.

A painting depicting a Roman naumachia by Ulpiano Checa.

A painting depicting a Roman naumachia by Ulpiano Checa. (1894) (Public Domain)

The Praetorian Guards and their Role in the Assassination of Caligula

It may be pointed out that the Emperor Claudius owed his throne partially to the Praetorian Guards. Claudius’ predecessor, Caligula, was assassinated, and the man who claimed the principal part in this deed was a tribune of a cohort of the Praetorian Guard by the name of Cassius Chaerea. According to Suetonius:

Gaius used to taunt him, a man already well on in years, with voluptuousness and effeminacy by every form of insult. When he asked for the watchword Gaius would give him "Priapus" or "Venus," and when Chaerea had occasion to thank him for anything, he would hold out his hand to kiss, forming and moving it in an obscene fashion.”

The assassination of Caligula.

The assassination of Caligula. (akgimages)

More Assassinations by the “Protectors of the Emperor”

Caligula’s assassination may have been the first time the Praetorians had a hand in an emperor’s murder (the second, if one were to believe Tacitus’ account which states that Tiberius was murdered by his Praetorian Prefect, Macro), but it was certainly not the last.

Later emperors murdered by the Praetorian Guard include Galba, Commodus, Caracalla, and Elagabalus. Thus, to a certain extent, the Praetorian Guards were the king-makers of Rome. In the early 4th century AD, however, they made a fatal mistake by supporting Maxentius’ claim to the Roman throne.

In 312 AD, Maxentius and his Praetorian Guards fought against Constantine at the Battle of the Milvian Bridge. During the battle, Maxentius was killed, and the Praetorian Guards were defeated. The unit was then disbanded by Constantine, and its remaining members were reassigned to the frontiers of the empire, thus ending their grip on power in Rome and roles as the Emperor’s private guards.

Schlacht bei der Milvischen Brücke by Pieter Lastman. (1613). Maxentius was killed and the Praetorian Guards were defeated at the Battle of the Milvian Bridge in 312 AD.

Schlacht bei der Milvischen Brücke by Pieter Lastman. (1613). Maxentius was killed and the Praetorian Guards were defeated at the Battle of the Milvian Bridge in 312 AD. (Public Domain)

Oddly enough, a recent sudy suggests that weather may have also played a role in the death of several of Rome’s emperors. It may be simply correlation, not causation, but researchers have found a lack of rain went hand in hand with 20% of the assassinations of 82 Roman emperors. The study published in Economic Letters suggests “lower precipitation increases the probability that Roman troops, who relied on local food supplies, starve. This pushes soldiers to mutiny, hence weakening the emperor’s support, and increasing the probability he is assassinated.” If he wasn’t killed by his angry army directly, the study says the emperor’s security would have been decreased as the soldiers lost their faith in his ability to provide them with sufficient food. That would have left the door open for other enemies to bring him down.

While interesting to consider, bad weather may not have been enough to incite the emperor’s guards to kill or abandon him. We cannot forget some of the other problems which may have made inspired assassination attempts, such as disease, war, and economic concerns. Or maybe they were just bad emperors.

Featured image: Proclaiming Claudius Emperor. (1867) By Lawrence Alma-Tadema. In one version of the tale of Claudius’ rise as the Emperor of Rome the Praetorian Guard found him hiding behind a curtain after Caligula’s death and proclaimed him as the emperor. (Public Domain)

By Ḏḥwty


Andrews, E., 2014. 8 Things You May Not Know About the Praetorian Guard. [Online]
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Smith, W., 1875. A Dictionary of Greek and Roman Antiquities: Praetoriani. [Online]
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Suetonius, The Lives of the Twelve Caesars: The Life of Caligula [Online]
[Rolf, J. C. (trans.), 1913. Suetonius’ The Lives of the Caesar: The Life of Caligula.]
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Suetonius, The Lives of the Twelve Caesars: The Life of Claudius [Online]
[Rolf, J. C. (trans.), 1913. Suetonius’ The Lives of the Caesar: The Life of Claudius.]
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Tacitus, The Annals [Online]
[Jackson, J. (trans.), 1925-37. Tacitus’ The Annals.]
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Wu Mingren (‘Dhwty’) has a Bachelor of Arts in Ancient History and Archaeology. Although his primary interest is in the ancient civilizations of the Near East, he is also interested in other geographical regions, as well as other time periods.... Read More

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