Rome

Rome mattered not only as the capital of a Mediterranean power but as a place where the book’s argument about institutions becomes visible: political participation, landholding, trade, and economic growth rose and fell together. In the Republic, citizen institutions and Mediterranean commerce supported prosperity, though slavery and senatorial dominance made that order deeply unequal. As power accumulated in the hands of emperors and their allies, citizens lost political influence, property rights became less secure, and trade and economic activity contracted.

Republican Rome and political participation

The Roman Republic was established after citizens overthrew their king, Lucius Tarquinius Superbus, around 510 BC. Its institutions distributed authority among elected magistrates, who served for a year and held office simultaneously, limiting any one person’s ability to consolidate power. Political representation was indirect and unequal, and slaves—perhaps a third of the population—had no rights or representation. Even with those exclusions, the Republic had pluralistic features: plebeians elected their own tribune, who could veto magistrates’ actions, convene the Plebeian Assembly, and propose legislation.

That political voice had been won through collective pressure. Plebeians, particularly soldiers, could withdraw to a hill outside Rome and refuse to cooperate until their complaints were addressed. This tactic mattered especially in wartime, when the state depended on their service. By the second century BC, the tribunate offered a channel through which common citizens could press claims about land and political rights. Rome’s institutional balance was limited, but it gave citizens some protection and helped create economic opportunities. Mediterranean trade flourished, and some ordinary Romans reached high incomes and enjoyed public services such as sewage and street lighting, even though most citizens and enslaved people lived near subsistence.

Trade, wealth, and the land conflict

The Republic’s expansion connected Rome to a broad network of port cities, from Athens, Antioch, and Alexandria in the east through Rome, Carthage, and Cadiz to London in the west. Shipwrecks and their cargoes record the growth of that commerce. Amphorae carried wine and olive oil, sometimes marked with information about their makers and dates. Near the Tiber, discarded vessels accumulated into Monte Testaccio, a hill formed from approximately fifty-three million amphorae. Greenland ice cores offer a different measure of the same expansion: atmospheric lead, silver, and copper rose from around 500 BC to a peak in the first century AD, evidence of extensive Roman mining.

The gains from expansion were distributed unevenly. Senators controlled lucrative provinces and owned large estates worked by enslaved people, many captured in Rome’s wars. Meanwhile, the Republic’s armies depended on smallholder citizen-soldiers. As campaigns lengthened, soldiers could be away from their farms for years; their households fell into debt, and land was abandoned or absorbed into senatorial estates. By the late second century BC, many landless citizens had gathered in Rome seeking work, while the wealth and political power of the landowning elite continued to grow. This conflict over land and the rights of common citizens explains why Tiberius Gracchus, himself an aristocrat, became an adversary of powerful senators.

In 133 BC, the plebeians made Tiberius Gracchus a tribune. His land-reform campaign challenged the existing distribution of land and sought to use funds bequeathed by the king of Pergamum to the Roman people for the reform commission. His bid to serve a second term gave senators a pretext to accuse him of seeking kingship. He and his supporters were attacked, and many were killed; Tiberius was among the first to fall. His death did not settle the underlying dispute. His brother Gaius later took up the cause and was also killed by landowners. The conflict resurfaced in the Social War of 91–87 BC, and the senator Lucius Cornelius Sulla suppressed demands for change while sharply curtailing the tribunes’ powers. Popular support for Julius Caesar in his later struggle with the Senate likewise drew on these unresolved tensions.

From Republic to imperial rule

The decisive break came in 49 BC, when Julius Caesar led his legion across the Rubicon, the river dividing Cisalpine Gaul from Italy. Rome fell to Caesar, and civil war followed. He won, but senators led by Brutus and Cassius murdered him in 44 BC. The Republic was never restored. Another civil war pitted Caesar’s supporters, especially Mark Antony and Octavian, against his opponents, and then Antony against Octavian. Octavian’s victory at Actium in 31 BC secured his supremacy. By the following year he ruled alone; known after 28 BC as Augustus, he established the Roman Empire while presenting his regime as a Principate, with himself as a first among equals.

The transition changed more than the name of the regime. It weakened institutions that had allowed common Romans to exercise political influence and helped make the economy more extractive. Augustus restructured the army in ways that made the plebeian secession tactic impossible. Under Tiberius, who succeeded Augustus in AD 14, the Plebeian Assembly was abolished and its powers transferred to the Senate. Political participation gave way to distributions of wheat and later olive oil, wine, and pork, alongside circuses and gladiatorial contests. The emperors also relied increasingly on the Praetorian Guard, a professional force that became an independent broker in imperial succession, sometimes through civil conflict and intrigue. Augustus strengthened the aristocracy, while the inequality that had fueled the crisis around Tiberius Gracchus persisted and may have deepened.

Insecurity, contraction, and historical significance

As authority concentrated at the center, ordinary property rights became less secure. Imperial territory included confiscated state land, which reached as much as half of the land in some parts of the empire. The concentration of power also made control of the imperial position more valuable and intensified struggles over succession. During the Year of the Five Emperors, Septimius Severus seized power from Didius Julianus, who had become emperor after Pertinax was murdered; Severus then defeated rival generals Pescennius Niger and Clodius Albinus in AD 194 and 197 and confiscated the property of his defeated opponents. Capable emperors such as Trajan, Hadrian, and Marcus Aurelius could slow decline, but they did not restore effective republican institutions. Marcus Aurelius was succeeded by Commodus, whose rule recalled the emperors Caligula and Nero.

The effects of instability appeared in the built environment and in people’s legal status. By the third century AD, every sizeable city in the empire had defensive walls; monuments were sometimes dismantled for stone to build fortifications. In Gaul, settlements that had moved from defensible hilltops to the plains after Rome’s arrival returned to hilltops as insecurity grew. Citizenship spread until nearly all inhabitants of the empire were citizens by AD 212, but this did not mean equal treatment: under Hadrian, different categories of citizen were subject to different laws, and citizens no longer exercised political influence as they had through republican assemblies. Slavery persisted, while increasing numbers of agricultural workers became semi-servile coloni tied to the land. The legal rights of landlords over them expanded: Constantine permitted landlords in 332 to chain a colonus suspected of trying to escape, and from AD 365 coloni needed their landlords’ permission to sell their own property.

The economic record shows expansion followed by contraction. The number of dated shipwrecks rose with Roman trade but fell from a peak of 180 to 20 by AD 500. Mediterranean commerce collapsed, while Greenland ice cores register a decline in lead, silver, and copper after their first-century AD peak. The Republic’s earlier growth rested on agricultural productivity, provincial tribute, and long-distance trade, rather than sustained technological progress. Romans adopted iron tools, literacy, plow agriculture, and building techniques, and developed cement masonry, pumps, and water wheels early in the Republic; thereafter technological change stagnated. Ship design and rigging changed little, ships continued to be steered with oars rather than stern rudders, and water power spread too slowly to transform the economy. Aqueducts and sewers perfected existing technologies rather than inaugurating new ones. In the book’s account, growth that did not rest on innovation and creative destruction could occur under partially inclusive institutions, but it could not last as political and economic rights eroded.

Rome’s history is therefore not a simple story of prosperity giving way to invasion. The book treats external military pressure as a symptom, not the original cause, of decline: during the Republic, Rome had faced powerful opponents such as Carthage. Its deeper explanation is institutional. The shift from a republic with restricted but meaningful political participation to a more concentrated imperial order weakened property security, sharpened elite conflict, and narrowed the basis for sustained economic growth. Rome’s rise and contraction show how the distribution of political power could shape both who benefited from prosperity and whether prosperity endured.