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I want to know something more about garrison at Rome (except praetorian cohorts and vigiles).

I know, that in Rome existed Urban cohorts, similar to Praetorians, in strenght of 500-1000, but whad did they do? Did they be policemans?

I also heard about Peregrini (something like secret police) and about frumentarii (couriers ?).

Does anyone know more about these units?
Not much. The Urban Cohorts were technically supposed to be under the Urban Prefect and permanently belonging to the city of Rome, while the Praetorians of course belonged with the emperor. I have never heard anything in particular about their duties, but would assume they functioned as a public order force for Roma and its countryside.

There were the frumentarii at the castra peregrina, soldiers on detached duty from the legions. Some authors despise them with a passion, presumably because they served as a kind of domestic intelligewnce unit. They were organised into a temporary numerus, and there seem to have been detached stations in other Italian cities as well as frumentarii serving in the legions themselves. Unfortunately, we only have a very sketchy idea of what they actually did. As with the later agentes in rebus, some interpretations have been more excitable than others. My personal guess is that they were basically snoops. You'd tell them 'find out something' and they'd go and do it. That kind of service was well established in the ancient world, and never highly regarded by the wealthy and powerful, who as a rule preferred to not be bothered. Mind you, despite everything it is conceivable that they were supply clerks. That is what the name means, after all.

Generally, I am still looking for a good study of ancient intelligence work. Some attempts have been made, but they mosty concentrated on scouting.

Also, do not forget the equites singulares Augusti. they were separate from the Praetoriansm, an elite guards cavalry unit. Horsemen, mostly peregrine, recruited heavily from the northern provinces - the locals must have hated them :-) )
Frumentarii were emperors couriers, but acted also as secret assassins and spies. As Carlton already noted, these were soldiers detached from their original, provincial legions for special duty to Rome. They were billeted in the castra peregrina. They were created probably under Trajan or under Hadrian at the latest. They were disbanded by Diocletian and replaced by agentes in rebus.

For other units in Rome, we must not forget the Germani corporis custodes - emperor’s German bodyguard. They were created by Augustus, then disbanded after the Varian disaster, but reformed soon afterwards, again disbanded by Galba, but reformed once again probably under Trajan.

The status of the peregrini is not certain. It is possible, that all men quartered in castra peregrina (frumentarii, speculatores and perhaps occasionally other men) were collectively called peregrini.

Carlton, have you read this book:
Austin, N J. E. - Rankov, N. B.: Exploratio. Military and political intelligence in the Roman world from the Second Punic War to the battle of Adrianople, London, 1995.

Still I haven't read it, so I can't tell how good it is, but I think it may be interesting for you. You can find a reviw here:

Thanks. I've read Exploratio and found it interesting, but its focus looked to me to be scouting and field intelligence gathering. Unfortunately, not what I'm interested in.
Hi all, thought I'd interject a bit on the Urban cohorts since they're a topic I've been working on as a PhD student. While primarily for Rome, two cohorts of urbaniciani were sent (one each) to Lyon and to Carthage. We often see them (in the rare moments when they are mentioned by our literary sources) involved in street fights or rioting. Herodian describes them as aiding in a fight with the civilians against, presumably, the equites singulares under Cleander. There are some strange incidents, primarily in the civil wars after Nero's death, when they're sent into the field with the Praetorians. Otho used them extensively and they seem to have done well, for a time but were eventually defeated.

The assumption about the Urban cohorts is that they were a sort of paramilitary police organised along the lines of the Praetorian cohorts (until the reign of Septimius Severus who seems to have initiated an administrative change). Early on, they probably mirrored almost all of the features in the Praetorian cohorts. After Severus, we are told by Cassius Dio that the strength of each Urban cohort becomes 1500 men (the Praetorians of the time were milliary strength at a nominal 1000 men per cohort).

I hope that helps somewhat, but I saw this thread and thought I'd post since it was on something that I am researching.

Best wishes,

Hi Michael,
it is possible, that the strength of praetorian cohorts was also increased to 1500 at the time of Septimius Severus.

Your post is very interesting. I've read somewhere, that the urban cohorts provided security at games and theatres in Rome. I would like to know the exact evidence we have for this. Could you, please, help me with this?

Hi Alexander,

No, at that time we are told, indirectly, in the same passage of Dio that the Praetorians were in 10 cohorts of 1000 men each. The Urban cohorts were given as four cohorts of 1500 men each. Dio was trying to describe the number of units in the Roman army as a whole but he was anachronistically ascribing this number of units in the Rome garrison to Augustus' reign (these numbers clash rather badly with Tacitus' own listing of the garrison in Rome in AD 23 in his Annales). The difference in sizes of Praetorian and Urban cohorts, due to Severus, may be due to his reforms of the Rome garrison and an attempt to keep these two corps of troops seperate and balance them against each other.

The exact passage of Dio would be: 55.21 in which he enumerates the units under Augustus. However, as I said, he is extrapolating from his own time back to Augustus' own time.

Tacitus' own description of the Rome garrison was of nine cohorts of Praetorians and three cohorts of urbaniciani. See Tacitus, Annals of Imperial Rome - 4.5 for this information.

We do have discussion of the Urban Prefect's duties in the Digest of Justinian, there are some entries culled from Gaius who wrote in the Severan period. Primarily they are 'police-keeping' duties and matters pertaining to maintaining public order in Rome and the surrounding regions.

Tacitus does mention, in the reign of Nero, that a cohort was taken from its post at a theatre (the location or name of that theatre is nowhere given) but, after disturbances, Nero was obliged to put the unit back in place. See Tacitus' Annals of Imperial Rome - 13.24 for the withdrawal of this unit.

I'm not exactly certain about the date there, I believe it is AD 55 or so but I don't have my thesis to hand at the moment to confirm the date (I'm on a public computer rather than my own). Dio also wrote, briefly, about that as well and I can track down the reference for you if you like.

I hope that helps and if you are interested in the Urban cohorts, I can suggest Helmut Freis' work (in German) on the cohorts and Fred C. Mench's unpublished PhD thesis on the cohorts. Mench's is primarily an epigraphical commentary but he does discuss some of the history and so does Freis though neither really go into as much depth as I would like. In addition, Edward Echols has written two articles that I know of about the cohorts (one on their creation and one on the two provincial urban cohorts, as he calls them). I can post the titles of those two when I get home and where you may get a hold of them. Also useful is Freis' own entry for the Urban cohorts in one of the supplements for the Realencyclopädie of Klassischen Altertumswissenschaft.

Best wishes,

Hi Michael,
as you mentioned, Dio wrote about Augustan Rome. Durry's opinion (followed by some other scholars), that Dio is extrapolating the situation of his own time, may but also may not be correct. Durry supports his view by calculations of the strength of praetorian cohorts from laterculi praetorianorum, but these calculation were (I believe quite convincingly) questioned (see Kennedy, D. L.: Some Observations on the Praetorian Guard, Ancient Society 9, 1978, 275-301.). There is an interesting theory, that the fact, that Dio writes about 10 units (and not 9) is caused by the speculatores, who at the time of Augustus had been a part of the praetorian guard and had been formed into one individual unit (i.e. had not been attached to individual praetorian cohorts as was later the case). Dio could simply regard them as the 10th unit.
The recalculations of Durry's numbers made by Kennedy show, that at the time of Septimius Severus the praetorian cohorts were probably 1500 strong.

Thank you for your info about the urban cohorts. If you could find the citation of Dio, i would appreciate it very much.
Thanks again.
Hi Alexandr,

Ah yes, I had forgotten about Kennedy and Durry. Kennedy's discussion was quite enlightening. Dio's passage dealing with the cohort at the games, presumably an Urban cohort, and I've treated it as such in my own work: 61.8. I hope you have found that useful and I aplogise again for forgetting Durry and Kennedy (more so when I have both Durry and Passerini sitting on my bookshelf and Kennedy's article in my desk).

Best wishes,

Hi Michael,
there's absolutely no need to apologise. Nobody's omniscient and I consider our discussion very worthwhile. And, after all, we're just talking about theories.
Thank you again for your help with urban cohorts.