"Daily life in the Roman Empire resembled daily life in the wild and wooly American West: no police in the streets, no deputies in the countryside, no public prosecutor. Every man had to defend himself and mete out his own justice, and the only practical solution for the powerless and the not-so-powerful was to place themselves under the protection of a strong patron."

—Paul Veyne, A History of Private Life, vol. I, p. 151.

Let's face it, I know nothing about the legal system. What I can glean so far is that it relies on petitions submitted to the local legal authority/-ies, which in Alexandria means no less a personage than the prefect. Although I have a hard time believing that the prefect of the whole province could be bothered to try every case of petty thievery in the city of Alexandria; I would therefore say there's probably a lesser magistrate who'd be responsible for that sort of thing. (The petition below is addressed to a centurion, rather far below the prefect!) Anyway, if you were to rob someone and be caught, then whoever caught you—local police or the person you robbed—would file a petition against you. If you were captured, you might be released on bail pending a court date, much like today. You would then be summoned to appear in court on a certain day—which could be a long time in the future, and your trial might not actually take place on that day.

Penalties could range from fines on up, near as I can tell. There were prisons. "For really serious crimes," N. Lewis writes, "slaves and free men of low estate might be condemned to hard labor in an army camp, mine, or quarry." ". . . and there are a few references to beatings ordered for violations of court orders."

An example of the sort of petition that might be filed: "To —————, centurion, from Soterichos son of ———— (son of Theon), of the village of Tebtynis. Some persons, in the manner of thieves, broke into my house in the village during the night preceding the 22nd of the present month Hathyr [i.e., today], seizing the opportunity of my sleeping away because of mourning for my daughter's husband. [They obtained entrance] by removing the nails from the doors, and they carried off everything I had in my house, a detailed list of which I will reveal when required. Therefore I submit this and ask that the due investigation be made by the proper parties, so that I may obtain relief from you. [Date, 18 November AD 176.]" (Lewis, p. 78.)

Petronius mentions a prætor in The Satyricon, described as a combination of policeman and judiciary. The person who held this title was elected to a region annually, and had consular (i.e., supreme) powers in that region.

Also mentioned are courts where people can be brought up on charges and ordered to pay delinquent debts. This seems to have been the major occupation of the courts—they also covered such things as robberies.