… before we dive into how Roman citizenship worked, we need to have a baseline for how citizenship worked in most ancient polities so we can get a sense of the way Roman citizenship is typical and the ways that it is different. In the broader ancient Mediterranean world, citizenship was generally a feature of self-governing urban polities (“city-states”). Though I am going to use Athens as my “type model” here, citizenship was not exclusively Greek; Italic communities; Carthage seems to have had a very similar system. That said, our detailed knowledge of the laws of many of the smaller Greek poleis is very limited; we only know that the Athenian system was regarded more-or-less as “typical” (as opposed to Sparta, consistently regarded as unusual or strange, though even more closed to new entrants than Athens).

Citizenship status was clearly extremely important to the ancients whose communities had it. Greek and Roman writers, for instance, do not generally write that “Athens” or “Carthage” do something (go to war, make peace, etc), but rather that “the Athenians” or “the Carthaginians” do so – the body of citizens acts, not the state. Only citizens (or more correctly, adult citizen-males) were permitted to engage in direct political activity – voting, speaking in the assembly, or holding office – in a Greek polis; at Athens, for a non-citizen to do any of these things (or to pretend to be a citizen) carried the death penalty. This status was a jealously guarded one. It had other legal privileges; as early as Draco’s homicide law (laid down in 622/1) it is clear that there were legal advantages to Athenian citizenship. After Solon (Archon in 594), Athenian citizens became legally immune to being reduced to slavery; non-citizen foreigners who fell into debt were apparently not so protected (for more on this, see S. Lape, Race and Citizen Identity in the Classical Athenian Democracy (2010), 9ff). Citizenship, for those who had it, was likely the most important communal identity they had – certainly more so than linguistic or ethnic connections (an Athenian was an Athenian first, a Greek a distant second).

So then who got to be a citizen? At Athens, the rules changed a little over time. Solon’s reforms may mark the point at which citizenship became the controlling identity (Lape, op. cit. makes this argument). While Solon himself briefly opened up Athenian citizenship to migrants with useful skills, that door was soon slammed shut (Plut. Sol. 24.2); citizenship was largely limited to children with both a citizen father and a citizen mother (this seems to have been more flexible early on but was codified into law in 451/0 by Pericles). Bastards (the Greek term is nothoi) were barred from the citizenship at least from the reforms of Cleisthenes in 509/8. This exclusivity was not unique to Athens; recall that Spartiate status worked the same way (albeit covering an even smaller class of people). Likewise, our Latin sources on Carthage – no Carthaginian account of their government (or indeed any Carthaginian literature) survives – suggest that only Carthaginians whose descent could be traced to the founding settlers had full legal rights. Under the reforms of Cleisthenes (509/8), each Athenian, upon coming of age, had their claim to citizenship assessed by the members of their respective deme (a legally defined neighborhood) to determine if they were of Athenian citizen stock on both sides.

It is worth discussing the implication of those rules. The rules of Athenian citizenship imagine the citizen body as a collection of families, recreating itself, generation to generation, with perhaps occasional expulsions, but with minimal new entrants. Citizens only married other citizens because that was the only condition under which they could have valid citizen children. Such a policy creates a legally defined ethnic group that is – again, legally – incapable of incorporating or mixing with other groups. In this sense, Athenian citizenship, like most ancient citizenship, was radically exclusionary. Thousands of people lived permanently in Athens – resident foreigners called metics – with no hope of ever gaining Athenian citizenship, because there were no formal channels to ever do so.

(As an aside, it was possible for the Athenian citizenry to admit new members, but only by an act of the Ekklesia, the Athenian assembly. For a modern sense of what that means, imagine if it was only possible to become an American citizen by an act of Congress (good luck with the 60 votes to break a filibuster!) that names you, specifically as a new citizen. We don’t know exactly how many citizens were so admitted into the Athenian citizen body, but it was clearly very low – probably only a few hundred through the entire fourth century, for instance. In practice, this was a system where there were no formal mechanisms for naturalizing new citizens at all, that only occasionally made very specific exceptions for individuals or communities.)

In short, while there were occasional exceptions where the doorway to citizenship in a community might open briefly, in practice the citizen body in a Greek polis was a closed group of families which replaced themselves through the generations but did not admit new arrivals and instead prided themselves on the exclusive value of the status they held. The fact that the citizen body of these poleis couldn’t expand to admit new members or incorporate new communities but had become calcified and frozen would eventually doom the Greeks to lose their independence, since polities of such small size could not compete in the world of great kingdoms and empires that emerged with Philip II and Alexander.

Bret Devereaux, “Collections: The Queen’s Latin or Who Were the Romans, Part II: Citizens and Allies”, A Collection of Unmitigated Pedantry, 2021-06-25.