--- title: Cohortes Urbanae: Ancient Rome's Police Force author: Mark Cartwright source: https://www.worldhistory.org/Cohortes_Urbanae/ format: machine-readable-alternate license: Creative Commons Attribution-NonCommercial-ShareAlike (https://creativecommons.org/licenses/by-nc-sa/4.0/) updated: 2025-04-18 --- # Cohortes Urbanae: Ancient Rome's Police Force _Authored by [Mark Cartwright](https://www.worldhistory.org/user/markzcartwright/)_ The *cohortes urbanae* (urban cohorts) were a body of troops garrisoned at [Rome](https://www.worldhistory.org/Rome/), which was created by [Augustus](https://www.worldhistory.org/augustus/) to provide additional security for the emperor and [city](https://www.worldhistory.org/city/) in general. Expanding in the reigns of subsequent emperors the force was responsible for maintaining public order in the capital and other [cities](https://www.worldhistory.org/city/) they were stationed at. Effectively acting as a police force it was also occasionally employed in battles and even involved itself in the succession of emperors. ### Creation Near the end of his reign (27 BCE - 14 CE), Augustus created the first three urban cohorts, likely recruiting them from the existing [Praetorian Guard](https://www.worldhistory.org/Praetorian_Guard/) (*cohortes praetoriae*) which was also stationed in Rome. The precise date of their foundation is not known, but the first reference in [literature](https://www.worldhistory.org/literature/) is from [Suetonius](https://www.worldhistory.org/Suetonius/) who mentions that each member received 500 sesterces in Augustus' 13 CE will. As there were nine cohorts of the Praetorian Guard, the urban cohorts were given the numbers X, XI, and XII, which were maintained even when the Guard was later expanded by another three cohorts. Besides providing an additional military force which the emperor could call on in cases of emergency or revolt, they would later be used, on occasion, in both civil and foreign wars by later emperors. ### Command Structure & Camp The urban cohorts were commanded by the urban prefect (*praefectus urbi*). As this position held senatorial rank, the holder was above the Praetorian prefect and he was responsible for all criminal cases not just in Rome but all of [Italy](https://www.worldhistory.org/italy/). Thus the commander of the urban cohorts had significant power, and when emperors were absent on campaign, they were, in effect, the most senior officer in the capital. Each cohort was commanded by a [tribune](https://www.worldhistory.org/Tribune/) and six centurions. As with the Praetorian Guard, members were largely recruited from Italy to ensure greater loyalty. The term of service was 20 years, and they received 50% more pay than ordinary legionaries but half the pay of the more prestigious Praetorian Guard, with whom they shared a camp, the *castra praetoria*, in the north-eastern suburbs of Rome. In 270 CE the urban cohorts were given their own camp in the city by [Aurelian](https://www.worldhistory.org/Aurelian/), the *castra Urbana*, located on the Campus Martius. It is likely, too, that small detachments were stationed in watchhouses across the city on a rotation basis. [ ![Castra Praetoria](https://www.worldhistory.org/img/r/p/750x750/6100.jpg?v=1768078875) Castra Praetoria Ross Cowan (CC BY-NC-SA) ](https://www.worldhistory.org/image/6100/castra-praetoria/ "Castra Praetoria")### Function The primary function of the *cohortes urbanae*, as with most other troops not involved directly in combat, was to maintain public order. There are no surviving records which detail exactly what the urban cohorts did, but one can imagine in a large city like Rome there were plenty of instances of minor crime and disturbances to deal with as well as crowd-control duties at such popular events as [gladiator](https://www.worldhistory.org/gladiator/) games at the [Colosseum](https://www.worldhistory.org/Colosseum/) and [chariot](https://www.worldhistory.org/chariot/) races at the [Circus Maximus](https://www.worldhistory.org/Circus_Maximus/). There might also have been more serious events to deal with such as food riots and demonstrations. Their role as a body which kept public order is largely assumed from the absence of any other military function or guard duties related to the emperors rather than direct evidence from [Roman](https://www.worldhistory.org/disambiguation/Roman/) writers. In addition, the fact that their commander was responsible for criminal cases in the city would suggest that the urban cohorts would have sought out and arrested criminals for trial. The role of policing the capital was a new one, though, and the difficulties of what exactly that entailed is evident in the resignation of the prefect Valerius Messalla Corvinus, after only six days in office on the grounds that he was not clear how to fulfil his duties. The first permanent commander of the urban cohorts was Lucius Calpurnius Piso, appointed in 13 CE. [ ![Street Riot](https://www.worldhistory.org/img/r/p/500x600/6164.png?v=1758151692) Street Riot The Creative Assembly (Copyright) ](https://www.worldhistory.org/image/6164/street-riot/ "Street Riot")### Evolution As with the Praetorian Guard, the urban cohorts found time to meddle in politics and they supported or defied certain emperors, starting with the turmoil which followed [Caligula](https://www.worldhistory.org/Caligula/)'s assassination in 41 CE. [Claudius](https://www.worldhistory.org/claudius/) gained their support, and perhaps as a consequence, they were expanded with another cohort added to their ranks. During the reign of [Nero](https://www.worldhistory.org/Nero/) (54-68 CE) they were expanded again and this time reorganised into seven 500-man cohorts bearing the numbers X to XVI. The tinkering continued with [Vitellius](https://www.worldhistory.org/Vitellius/) reshuffling the force into four 1000-man cohorts in 69 CE and mixing in some veteran legionaries. With Rome now perhaps a little overpacked with troops, [Vespasian](https://www.worldhistory.org/Vespasian/) and his successors [Titus](https://www.worldhistory.org/disambiguation/Titus/) and [Domitian](https://www.worldhistory.org/domitian/) decided to remove two cohorts and station one each at [Carthage](https://www.worldhistory.org/carthage/) and Lugdunum (modern Lyon), both provincial capitals, and the latter a major mint. At certain times, probably to protect grain shipments, urban cohorts were deployed at [Ostia](https://www.worldhistory.org/Ostia/) and Puteoli too. Yet another expansion, in fact the last change, came during the reign of [Septimius Severus](https://www.worldhistory.org/Septimius_Severus/) (193-211 CE) with four cohorts being maintained but each now consisting of 1,500 men. The demise of the urban cohorts came in the aftermath of the [Battle](https://www.worldhistory.org/disambiguation/battle/) of Milvian Bridge in 312 CE. They and the Praetorian Guard had supported Maxentius, and so the victor [Constantine I](https://www.worldhistory.org/Constantine_I/) disbanded the Praetorians and greatly reduced the significance of the urban cohorts in Rome. The two cohorts in the provinces had likely already been disbanded a century or so earlier. #### Editorial Review This human-authored definition has been reviewed by our editorial team before publication to ensure accuracy, reliability and adherence to academic standards in accordance with our [editorial policy](https://www.worldhistory.org/static/editorial-policy/). ## Bibliography - Bagnall, R.S. *The Encyclopedia of Ancient History.* Wiley-Blackwell, 2012 - Grant, M. *The History of Rome.* Faber & Faber, 1991 - [Hornblower, S. *The Oxford Classical Dictionary.* Oxford University Press, 2012.](https://www.worldhistory.org/books/0199545561/) - [Southern, P. *The Roman Army.* Amberley, 2016.](https://www.worldhistory.org/books/1445655330/) ## About the Author Mark is WHE’s Publishing Director and has an MA in Political Philosophy (University of York). He is a full-time researcher, writer, historian and editor. Special interests include art, architecture and discovering the ideas that all civilizations share. ## Timeline - **c. 13 CE**: [Augustus](https://www.worldhistory.org/augustus/) creates the [cohortes urbanae](https://www.worldhistory.org/Cohortes_Urbanae/) in [Rome](https://www.worldhistory.org/Rome/) to help maintain public order. - **270 CE**: The [cohortes urbanae](https://www.worldhistory.org/Cohortes_Urbanae/) in [Rome](https://www.worldhistory.org/Rome/) is given its own camp, the castra Urbana. - **312 CE**: [Constantine I](https://www.worldhistory.org/Constantine_I/) reduces the [cohortes urbanae](https://www.worldhistory.org/Cohortes_Urbanae/) of [Rome](https://www.worldhistory.org/Rome/). ## Cite This Work ### APA Cartwright, M. (2016, December 16). Cohortes Urbanae: Ancient Rome's Police Force. *World History Encyclopedia*. [https://www.worldhistory.org/Cohortes\_Urbanae/](https://www.worldhistory.org/Cohortes_Urbanae/) ### Chicago Cartwright, Mark. "Cohortes Urbanae: Ancient Rome's Police Force." *World History Encyclopedia*, December 16, 2016. [https://www.worldhistory.org/Cohortes\_Urbanae/](https://www.worldhistory.org/Cohortes_Urbanae/). ### MLA Cartwright, Mark. "Cohortes Urbanae: Ancient Rome's Police Force." *World History Encyclopedia*, 16 Dec 2016, [https://www.worldhistory.org/Cohortes\_Urbanae/](https://www.worldhistory.org/Cohortes_Urbanae/). ## License & Copyright Submitted by [Mark Cartwright](https://www.worldhistory.org/user/markzcartwright/ "User Page: Mark Cartwright"), published on 16 December 2016. The copyright holder has published this content under the following license: [Creative Commons Attribution-NonCommercial-ShareAlike](https://creativecommons.org/licenses/by-nc-sa/4.0/deed.en). This license lets others remix, tweak, and build upon this content non-commercially, as long as they credit the author and license their new creations under the identical terms. 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