Praetorian Guard

In Ancient Rome, the Praetorian Guard or Imperial Praetorian Guard was a unit of the Roman Army formed of elite soldiers initially recruited in Italy. These units originated from the small group of men around which surrounded the republican magistrates, known under the designation of praetor, and also originated from around roman legion camps where the legion commandant's (Latin : Prætorium) main tent garrisoned when engaged in battle campaigns. The Praetorian Guard is one of the most famous military units in Roman History.

They were first hand picked veterans of the roman army in charge of providing close protection security details to the Emperor and accompanied him on war campaigns. Due to their more robust infantry armor, they were often sent on war campaigns battling alongside supporting legions. They also served as secret police protecting the civic administrations and rule of law imposed by the Senate and the Emperor. The title was already used during the Roman Republic for the guards of Roman generals since the rise to prominence of the Scipio family around year 275 BC. The Guard was dissolved by Emperor Constantine I in the 4th century. They were distinct from the Imperial Germanic bodyguard which provided close personal protection for the late Western Roman emperors.

Under the Roman Republic
During the Roman Republic, there was no permanent guard charged with the protection of military general officers. However, certain military officers chose to encircle themselves with soldier guards to ensure their security, giving birth to the first Praetorian Cohortes. In case of battle, these cohorts would intervene as a final reserve. The consuls were ordinarily protected by the lictors, whom would remain around their tents in the army.

At the siege of Numance, Scipio Aemilianus formed a troop of 500 men for his personal protection, as sorties were often quite dangerous for the upper ranks. This usage was then emulated and spread, as Roman generals occupied their positions for longer periods of time. Accordingly, this guard was referred to as Cohors Prætoria.

At the end of the year 40 BC, Octavian (the future Augustus) and his rival Mark Antony both operated a number of Praetorian units organized individually. According to Appian, amongst them were veterans forming cohorts. Mark Antony had three cohorts in the Orient and in 32 BC, he issued coins in honor of his Praetorians. According to Paul Orose, Octavian had five cohorts at Actium.

Following his victory at Actium, Octavian merged his forces with those of his adversary in a symbolic reunification in the army of Julius Caesar.