“Crime” lacks a fully agreed definition across modern societies, but competing versions tend to stress notions like punishment, protection of public or collective interests, and a pervasive role for the state in proceedings. Over time the Romans used a series of different procedures (successively, trial before the assemblies, by specialized juries, or by imperial inquisitors) to try most of their offences that would be more or less recognizably criminal today. Substantively, the core of this group were offences against the state in an institutional sense (e.g., sedition, electoral malpractice, abuse of public office, forgery). Over time it also came to include an increasing number of (personal) crimes of violence. Some core modern criminal offences such as forms of theft and forgery of private documents came to be grouped in with these only at a very late date and incompletely. “Moral” offences that are treated as criminal more sporadically today (e.g., use of intoxicants, gambling, prostitution) were not criminalized. Penalties in earlier periods included fines, civic disgrace, and exile; later periods introduced finer differentiation of penalties, as well as execution. Imprisonment was not a formal penalty.