Thank you for looking into answering my questions. My understanding of the distribution of the late roman army was that they were primarily stationed in or around the hinterland of the frontier provinces or near imperial capitals i.e. outside of Constantinople. The army would billet near or in frontier cities during the non campaigning winter season.
Modest, but important cities, like Athens were far from the frontiers, but were walled, even after the Heruli sacking in 267 AD. Who manned these walls in peacetime as they were far from the frontiers or did roman units need to be massed there if an incursion occurred?
How was public order maintained in cities without military units especially during riots etc? For instance, did law courts have armed 'militia' or serving 'officers' who could arrest, jail and/or punish criminals?
I appreciate that I may be asking a number of questions here, but the core problem is around defense and maintaining of order and the sources I have been reading suggest that most cities were governed by solely civil officials who may have had no access to armed 'officers' to exercise their authority if the need should arise.
Many thanks for considering my questions. Kind Regards, Matthew.
The Roman army wasn't exactly a police force, not in the sense of policing cities.
Roman cities tended to have a civilian "militia" known as the Vigiles, typically organized into a cohort. They more or less did everything from minor policing to firefighting. There are a couple of cases where we even see them repelling a small barbarian raid or two.
That being said, the army often did man cities. Most Roman armies in the 4th-5th century numbered 25,000 men each, and you can't just increase the population of a single city by 33%. When not on campaign individual units would be billeted out (a system known as hospitalitas which would serve as the basis for barbarian settlement) in multiple locations. Many of these stations for the field armies are listed in the Notitia Dignitatum, but we know they were generally put into cities in the Po River Valley, southeast Thrace, Northwest Turkey, Syria, Tunisia, and the region around Lyon. They also moved around a lot to avoid having them become permanently tied to one location. But the Roman strategy was defense in depth, and the Barbarians usually didn't have any real siege capability until the mid-5th century, so it was easier to keep the field armies concentrated and deploy them as needed than to send units to garrison cities.