"Is it lawful for you to scourge a man that is a Roman, and uncondemned?" In the Acts of the Apostles (King James Version, 1611), the apostle Paul asks this of a Roman officer about to have him flogged in Jerusalem, and the officer backs off in alarm. The scene shows what Roman citizenship meant: a set of legal protections that travelled with you. Rome was unusual among ancient states in how widely it came to share that status, and also in how deeply it depended on people who had no rights at all.

What citizenship gave

A male Roman citizen could vote in the assemblies (if he could get to Rome), serve in the legions, make contracts and marriages valid in Roman law, and resist summary punishment. Citizens had the right of provocatio, an appeal to the people against a magistrate's punishment, and under the empire an appeal to the emperor; Paul famously appealed to Caesar and was sent to Rome for trial. Women were citizens too: they passed citizenship to their children and could own property, though they could not vote or hold office.

Tiers of belonging

Rome did not treat everyone it ruled alike. Between full citizens and outsiders sat communities with "Latin rights," which carried some citizen privileges, and the Italian allies, who fought in Rome's wars without a vote in its decisions. Resentment built. When reformers proposed giving the allies citizenship and the Senate blocked it, many allies rebelled. The Social War of 91 to 88 BC ended with Roman citizenship extended to nearly all free Italians south of the Po River. Its name comes from socii, the Latin for allies. Rome won the fighting and conceded the main demand.

Under the empire, citizenship spread through army service, grants to towns and favors to local elites. In AD 212 the emperor Caracalla granted citizenship to almost all free inhabitants of the empire, by a decree called the Constitutio Antoniniana. The historian Cassius Dio suspected a motive: new citizens owed the inheritance tax. Still, a status that began with one city now covered tens of millions of people from Britain to Syria.

Slavery at the heart of Rome

Rome was a slave society, meaning that slaves were not a marginal group but central to the economy. Most Roman slaves were captives taken in war; others were born to enslaved mothers, seized by pirates or abandoned as infants. Conquest flooded Italy with captives: after one campaign in Epirus in 167 BC the general Aemilius Paullus reportedly enslaved 150,000 people. Historians estimate that slaves made up perhaps 15 to 35 percent of the population of Roman Italy in the late Republic, though the numbers are much debated. Slaves worked as farmhands and miners, and also as household servants, secretaries, doctors and teachers. Rich Romans built latifundia, large estates worked by gangs of slaves, which helped push many small farmers off the land.

Roman law treated a slave as property. An owner could beat, sell or even kill a slave with little restriction until imperial laws limited some of the worst abuses. Yet Rome also had an unusual practice. A slave formally freed by a Roman citizen usually became a Roman citizen too, with some limits, and the children of freed slaves were full citizens. Freed slaves, called freedmen, formed a large class of shopkeepers, craftsmen and even rich businessmen. This mobility did not so much soften the system as stabilize it: the hope of freedom encouraged obedience.

Revolts

Slaves resisted in many ways, from running away to sabotage. Two great revolts shook Sicily in the second century BC. The most famous rising came later. Spartacus, a Thracian gladiator, broke out of a gladiator school at Capua in 73 BC with some seventy companions. Runaways and rural workers joined him, and his army grew to tens of thousands and defeated several Roman forces. Marcus Licinius Crassus crushed the revolt in 71 BC, and about 6,000 captives were crucified along the Appian Way between Capua and Rome.

Worked example: what did Spartacus want?

Modern readers often picture Spartacus leading a war to abolish slavery. The ancient sources, written by his enemies, suggest something different. His army marched north toward the Alps, perhaps so its members could scatter to their homelands, then turned back south. The sources show no program to end slavery as an institution, and ancient slave rebels sometimes kept slaves of their own. Does that make the revolt less meaningful? Apply this level's distinctions. Spartacus's followers were claiming freedom for themselves in a world where almost no one, slave or free, imagined a society without slavery. Even Stoic writers who insisted that slaves shared a common humanity did not call for abolition. The revolt shows both the human refusal to be property and how hard it is to imagine a different world from inside the one you know. Later writers, revolutionaries and filmmakers turned Spartacus into a symbol of liberation, which tells us as much about their own times as about his.