Hellenism achieved its most enduring political expression in the Roman Empire.  This chapter discusses how Rome translated Greek ideas into institutions that could support a world state with a common culture.

The Republic took the fist steps toward political and legal universalism.  After the Republic was declared, the Struggle of the Orders broke out, through which plebeians won legal equality with patricians.  An oligarchy of patricians and leading plebeians led Rome through its first period of expansion, during which it conquered Italy, Carthage, and the Hellenistic kingdoms.  Millions of slaves poured into Italy, many of them Greeks who introduced their masters to Hellenic culture.  After this initial wave of conquest, the Republic turned in on itself.  An agricultural crisis led to a series of civil upheavals, during which peasants fought for land reform and generals for political advantage.  Julius Caesar finally took over the state, ruling as dictator until he was murdered by a group of senators.  Civil war again erupted, from which Octavian Caesar emerged the victor.

Octavian then founded the Empire that endured for nearly 500 years.  Ruling in the guise of Republican government, Octavian, using the title Augustus, reformed the army, fought corruption in the provinces, kept the peace, and built roads and other public works.  Augustus also extended the rule of law throughout the empire, such that even slaves and women enjoyed legal rights unprecedented in the ancient world.  The peaceful world community of the Pax Romana began its long decline in the third century A.D. As the army degenerated into an unruly rabble, the government lost its power to hold the provinces together, fend off barbarian invasions, and avert the economic crises those upheavals occasioned.  After a temporary calm under Diocletian and Constantine, the western empire finally collapsed to tribal invasions.

Roman culture was marked by creative assimilation of Greek philosophy, art, and literature.  The Epicureanism of Lucretius spoke to late Republican disgust with civil strife but ran counter to Roman ideals of civic virtue.  Cicero's Stoicism addressed the latter, as well as the emerging idea of the Roman state as a world society.  Emulating Thucydides, Sallust wrote histories that attempted to account for the decline of Republican virtues.  Plautus and Terence wrote New Comedy in the style of Menander, and Catullus fashioned a variety of Greek-influenced poetry, most notably Sapphic love lyrics to his mistress.  During the Pax Romana, Golden Age authors perfected Latin poetry and prose.  Through his Homeric epic, the Aeneid, Virgil glorified Augustus, the founding of the Empire, and Roman virtue, as did Livy in his History of Rome.  In his Epodes and Odes, Horace satirized stupidity and licentiousness and instructed friends on how to achieve the virtuous good life.  Ovid composed a variety of mythological and erotic poetry, including the Ars Amatoria for which Augustus exiled him.  The Silver Age poet Martial wrote witty, caustic epigrams of practical wisdom, while his contemporary Juvenal composed savage satires against social and political evils.  Tacitus was the most important historian of the age, whose works denounced the imperial system and promoted Republican ideals.

Pax Romana philosophy and science also displayed the Roman debt to Greek rational humanism.  Stoicism was the principal philosophy, and its leading exponents were Seneca, who wrote on subjects ranging from cosmology to the inhumanity of gladiatorial combat, and the emperor Marcus Aurelius, who sought in Stoicism the moral strength to rule.  Unlike Seneca and other early Stoics, he gave Stoicism a religious turn by transforming the divine Logos from an intellectual to a moral necessity.  The leading scientific thinkers were Ptolemy, whose astronomical system accounted for most of what astronomers had observed to that point, and Galen, the physician whose rational study of human and animal bodies enlarged understanding of anatomy.

Rome's most unique achievement was its legal system.  During the early Republic, the jus civile developed as a uniform criminal and civil code applying to all citizens.  As the Republic expanded and gave way to the Empire, the laws of the original Twelve Tables were amplified by legal decisions, emperors' rulings, and commentaries by theorists who applied Greek methods of rational analysis.  As Rome expanded further, the jus gentium emerged, drawing upon traditions throughout the empire.  Jurists identified this "law of nations" with Stoic natural law, thus giving a rational legal foundation to the imperial world state.

During the second century A.D., the mythic-religious world view began to challenge Greek rational humanism.  Uninspired by the Imperial peace and dissatisfied by rational accounts of the world, many Romans turned to Eastern mystery religions for communal fulfillment, moral guidance, and personal salvation.  The most important of these cults was Mithraism, which offered, especially to men, a clear moral system and the promise of eternal life.  This new spiritualism also affected philosophy.  Through the teachings of Plotinus, Neoplatonism emphasized the otherworldly side of Plato's thought, arguing that individuals could achieve union with the Good not through reason but through a mystical leap of the purified soul.

The spirit of creative assimilation is most vividly represented through Roman architecture and art.  Roman architects borrowed Greek and Near Eastern designs and techniques and adapted them to build larger and more elaborate buildings.  For example, experiments with the arch enabled the Romans to build monumental public structures such as aqueducts, the Colosseum, and the domed Pantheon.  Domestic architecture included elaborate private villas for the wealthy and storied tenements that provided quarters for growing urban populations.  Sculptors extended Hellenistic realism through portrait sculptures that reproduced the subject's every feature.  They also displayed Near Eastern influence in portraits that idealized emperors.  Narrative reliefs glorified emperors' deeds while experimenting with techniques to represent perspective.  Roman pictorial artists also adopted Hellenistic realism, creating illusory stone surfaces on plaster walls, pictures of closely observed landscapes, and mosaics that imitated the effects of natural light.

The Greek tradition passed to Western civilization through Rome.  The idea of a world state continued to influence political figures, and the work of Roman artists and architects preserved the Hellenic tradition for later generations.  Latin became the language of Western intellectual life and the Romance languages evolved from it.  Finally, Rome laid the foundation of Western legal codes and helped establish Christianity as the central religion of the West.