In the 4th century BC, the Athenian assembly debated whether to align with King Philip II of Macedonia, who had begun invading Greek city-states. Isocrates hoped to unite the bickering city-states and believed Philip could lead a war against longtime enemy Persia. Echoing Philip’s own argument, he contended that the Macedonian king in fact was Greek because his ancestor was Heracles and his family came from the southern Peloponnese city Argos. Demosthenes, on the other hand, argued against joining Philip, who, the orator said, threatened Greek liberty, hailing from a “barbaric,” or non-Greek, state.

Studying the assembly debates for a 2001 paper on ancient Macedonia, classics professor and chair Jonathan Hall had an epiphany of sorts: “I realized,” he says, “that the definition of who’s a Greek was changing.” While Isocrates based his traditional argument on bloodlines, Demosthenes used a newer, cultural definition: Philip and the Macedonians were less civilized. They didn’t act like Greeks, therefore they were not.

Hall’s realization sparked the theories that shape his book Hellenicity: Between Ethnicity and Culture (2002), which in April won the U of C Press’s Gordon J. Laing Prize, given to the Chicago faculty author who adds the greatest distinction to the Press during the preceding three years. The faculty board chose Hellenicity, says Alan Thomas, editorial director for humanities and science, because it “had such strong reviews” and, though about ancient culture, “has a lot of relevance for how we understand ethnicity today.” A Hellenic identity, Hall contends, emerged in the early 6th century BC—later than most scholars have maintained. Further, he says, the definition of that identity changed, from an ancestral to a cultural basis, during the 5th century BC.

Many historians believe that the Greek language’s arrival correlates with the Hellenic identity. They commonly cite 2100 BC as the date Greek speakers arrived in mainland Greece. (A minority view places the language’s birth closer to 1600 BC, the date of the earliest evidence of Greek writing, but “all that might mean is that nobody wrote Greek before this period,” Hall argues, “not that nobody spoke it.”) A common language, to Hall, does not necessarily mean a common sense of identity. “Just because you speak something,” he says, “doesn’t mean you feel an affinity” with all others who speak it.

Another widespread view is that Hellenic identity emerged in the 8th century BC, when the Greeks formed colonies in southern Italy and Sicily. “The idea,” Hall says, “is that as the Greeks met people different from them, they started to think, ‘what makes us us?’” Yet Greek settlers, rather than carrying “a ready-formed sense of being Hellenic,” he writes, more likely “regarded themselves as émigrés from particular cities (Khalkis, Korinth) or regions (Krete, Lokris).” Archaeological evidence, moreover, suggests that the Greeks got along relatively well with the indigenous people they encountered, even intermarrying. It was hardly an environment, he believes, that would inspire a deep-rooted sense of otherness that in turn would form a group identity.

Scholars often connect the 8th-century theory to the formerly common belief that Homer composed his epics then. Because the Iliad and Odyssey span so much Greek geography, Hall explains, they seem “Panhellenic rather than parochial tales.” Yet Homeric experts, he says, now “believe that the two poems took the shape that’s familiar to us today rather later than the 8th century.”

For Hall, a Hellenic identity emerged when Greeks began referring to themselves collectively as “Hellenes” rather than Athenians or Spartans, for example. Though the term “Hellas,” denoting the geographic region, was used in the 7th century BC, literary evidence doesn’t find “Hellenes” until the early 6th century BC. The Thessalians, Hall speculates, spread its use. They already controlled the majority of seats on the Amphictyonic Council, a league of city-states that administered Apollo’s sanctuary at Delphi, and had begun to compete more frequently at the Olympic Games. By appropriating “Hellenes,” the Thessalians excluded their central-Greek neighbors and promoted “their own hegemonic claims” in the region.

In the 5th century the term’s definition began to change. Athens, Hall says, was a “key engineer” behind the shift from an ethnic, or descent-related basis, to a cultural one. The Athenians were establishing radical democracy, “at the expense of the elite who had previously governed the city.” One way the elites had paraded their privilege was by importing Persian goods. But once Greekness became defined in cultural terms—a switch so complete that by the 4th century BC, genealogies, once the basis for defining Greekness, had lost much significance—displaying Persian items meant associating with barbarians. “By making Greekness depend on cultural conformity,” Hall says, “the populace was in a sense taming the elite.”

Especially after the early-5th-century Persian War, an image of the non-Greek barbarian had emerged, with the Greeks defining themselves in opposition to those traits. They stereotyped Egyptians as “deceitful, Phrygians as cowardly, Persians as luxurious, Lydians as addicted to sex, Thrakians as savage and polygamous, and Skythians as crude and uncultured,” Hall writes. Though many scholars argue that the Greeks saw only two categories, themselves and barbarians, Hall contends that they more commonly considered identity on a continuum—one that allowed for climbing. A barbarian, he writes, “could ‘become’ Greek by adopting Hellenic practices, customs, and language.”

Developing the barbarian concept was one factor in changing Greek identity, but in addition, Hall says, “there comes a point where an imagined community becomes unimaginable.” As Greece expanded, a citizen at one end wouldn’t have felt an ethnic connection with his counterpart so many miles away. So the Greeks, Hall says, “were able to maintain—and in fact export and expand—their cultural identity, but at the expense of their ethnic identity.”

The idea that a geographic “ceiling” limits an ethnic group’s size has modern implications. Hall, now at work on The Blackwell History of the Archaic Greek World, ends Hellenicity with a note to politicians in his British homeland: ethnic groups, he writes, command more loyalty than cultural groups. That fact may “be some small comfort to the alarmists on the British right wing who fear the future dissolution of national consciousness” in an integrated Europe. Europeanness, like Greekness, is too big for each state to lose its ethnic identity.