Law Enforcement in the City of Rome
Today, the government is expected to maintain a police force to protect people from attacks on their person and property. That was not always the case in Roman times. During the Republic, it was a do-it-yourself activity. If someone suffered a physical injury or loss of property, they had to capture the criminals themselves, often with the help of friends or family, and bring the accused perpetrator before a magistrate for trial.
During both Republic and Empire, the streets of Rome were notoriously dangerous at night, and anyone of means traveling in the city after dark took their own force of slaves and often armed bodyguards with them.
During Augustus’s rule, the emperor was the first to create military units in the city of Rome to maintain the peace and protect the city from fires. These were divided into the Praetorian Guard (cohors praetoria), the Urban Cohorts (cohortes urbanae), and the Vigiles (vigiles urbani). As in the regular legions, the Praetorian Guards were freeborn citizens of Rome. The rank-and-file members of the Urban Cohorts and Vigiles units were mostly former slaves who received their citizenship when they were freed.
The Praetorian Guard was the elite military unit in Rome itself. After defeating Antony and Cleopatra, Octavian (later called Augustus) assigned them their role as political and criminal police of Rome. Augustus originally placed the Praetorians under the control of two praetorian prefects of equestrian rank, but later emperors reduced that to one. Part of the Guard traveled with the emperor when he left Rome, and part remained in Rome to discourage attempts by political rivals to replace the emperor in his absence. They often played a crucial role in deciding who would be the next emperor.
There were originally nine praetorian cohorts, but Caligula added three. Nero added two more, and Vespasian reduced the number to ten. A cohort was assigned to keep order at the Circus Maximus on race days, at the amphitheater while the games were in progress, and at the theater during performances. The city prison was run by the Praetorians, and executions decreed by the emperor or the Senate were their responsibility. A centurion and detachment of Praetorians might be sent far from Rome to carry out an execution, bringing the head back for public display in Rome.
In AD 10, Augustus formed a less prestigious unit that would serve as the daytime policemen and city gate guards. Urban prefect was a very prestigious position, and he was in charge of Rome when the emperor traveled. In many ways, he functioned like the mayor of Rome with important administrative responsibilities, including the free grain distribution to citizens. Under him were three and later four urban cohorts with numbers XI to XIV after Vespasian reduced the number of Praetorian cohorts to ten.
Some units were stationed in the city while others were sent to other cities where they would protect imperial assets, such as guarding grain shipments from Carthage. One cohort guarded the imperial mint at Lugdunum (Lyon) in Gaul. Each cohort was commanded by a tribune who reported to the urban prefect. Under each tribune were six centurions. The organization of each century paralleled that of a regular legion. The Urban Cohorts shared the praetorian fortress (castrum praetorium) with the Praetorian Guard. Their number and size varied with time, but in AD 120, there were four of them with 500 men under six centurions in each cohort.
Perhaps the most essential were the Vigiles, whose full name meant “cohorts that stay awake.” Originally formed in AD 6 by Augustus, they were both the nighttime police force and the fire brigade. They were under the command of the urban prefect. Rome was divided into 14 precincts (regios). Each of the seven cohorts of Vigiles served two precincts and were quartered in barracks in one of them. A cohort consisted of a thousand men under a tribune and several centurions.
Every precinct had cells and a torturer for extracting confessions from slaves and noncitizens. Most of the accused were tried at the stations by the Prefect of the Watch (praefectus vigilum). He was an equestrian who reported to the urban prefect, and he ranked second in power in the city. For some serious crimes and for accused people of the higher classes, some might be taken to a central jail or be allowed to post bail before a formal trial by the urban prefect.
The Vigiles patrolled Rome at night, watching for fires and criminal activity. Equipped with hand-pumped fire engines, grappling hooks, ladders, axes, shovels, and coiled-rope buckets sealed with pitch, they especially tried to keep fires from spreading to adjacent buildings.
With all wheeled traffic within a mile of the gates to Rome restricted to the late evening and nighttime hours, they also served as traffic police. Detachments were stationed in Rome’s port towns of Ostia and Portus as well.
In More Than Honor, Titianus is an equestrian tribune who has been serving for more than eight years in the XI Urban Cohort, reporting to the urban prefect Saturninus. He excels at investigating major crimes, and he has more than one murder and attempted murder to keep him busy in this story.
Dando-Collins, Stephen. Legions of Rome: The Definitive History of Every Imperial Roman Legion. New York: St. Martins Press, 2010,
Davis, William Stearns. A Day in Old Rome: A Picture of Roman Life. New York: Biblo and Tannen, 1925.