The Roman Empire refers to the post-Republican phase of ancient Roman civilization following the rise of its first emperor, Augustus, in 27 bce. With its power centered in ancient Rome, the empire reached its greatest extent under Trajan around 117 ce, when it took in all of the lands around the Mediterranean, the Black Sea, Mesopotamia, and extended into Britain.
Originating as a conglomeration of small pastoral communities scattered across seven neighboring hills along the Tiber River of Italy, Rome grew to become the capital of an empire that encompassed all the territories bordering on the Mediterranean Sea, extending from the British Isles to the Arabian Peninsula. Roman imperial authority combined the exercise of political and economic dominance with cultural and ideological sovereignty, enforced through strength of arms. The concept of “empire” in English-language usage ultimately derives from the Latin word imperium.
According to legend, the city of Rome was founded by Romulus and Remus, twin sons of the war god Mars, on 21 April 754/753 bce. Archaeological evidence indicates that the site was occupied by pastoralists and farmers as early as 1500 bce but not urbanized until the sixth century bce under the influence of cities to the north (established by the Etruscans in the area now known as “Tuscany”) and to the south (founded by Greek colonists in southern Italy and Sicily). Originally unified under an Etruscan king, the indigenous Latin-speaking inhabitants of Rome had established their city as a republic about 500 bce. The republic’s basic law code, the Twelve Tables (451/450 bce) defined and guaranteed the fundamental rights and responsibilities of all citizens, but the institutional structures of the state continued to evolve down to about 300 bce.
The senior magistrates of the Roman republic were the two consuls, elected annually and given chief executive power in civil and military matters, including the command of Rome’s armies. Other annually elected officials in the republic included the praetor, who supervised the administration of justice; the quaestors, who oversaw the state’s finances; and the aediles, who maintained public order and the city’s infrastructure (markets, trade, roads, sanitation, and state-sponsored public entertainments). Every five years two censors were elected to take a census of the entire citizen population and its possessions and to organize any major allocations of the state’s resources that might be necessary. Of these allocations, the distribution of public lands and the construction of new public buildings were the most important.
The censors were also responsible for overseeing the membership of the Senate, appointing new senators, and removing infamous ones from office. The Senate embodied the supreme authority of the Roman state, supervised and disciplined the actions of the magistrates, and possessed ultimate jurisdiction over domestic legislation and the state’s foreign relations.
The Senate and executive offices were dominated by the patricians, Rome’s hereditary elite. The ordinary citizens, or plebeians, were largely excluded from executive power but exercised a voice in public affairs through their membership in one or both of two citizen assemblies. The centuriate assembly encompassed all citizens whose material wealth was sufficient to require them to provide military service to the state. This electoral body voted for consuls, praetors, and censors. The tribal assembly included all free citizens and voted for quaestors and aediles. This assembly elected its own leaders, the tribunes, who represented the interests of the plebeians in state affairs and came to wield considerable power. The tribal assembly also had the right to propose, deliberate, and vote on new legislation, although such legislation had to be ratified by the Senate.
From its inception the Roman republic was a society prepared for war, with all eligible male citizens expected to bear arms for the state. The Senate had the power to appoint a dictator, an official who would wield absolute power in the state for up to six months in order to see it through a severe crisis, usually violent in nature. The wars during the early centuries of the republic were mostly defensive, and in 390 bce an army of Gauls briefly took Rome itself, but during the third century the republic began its expansion into a territorial empire. The entire Italian peninsula south of the Po River had come under Roman dominion by 264 bce. The three Punic Wars fought between Rome and the empire of Carthage (264–241 bce, 218–201 bce, 149–146 bce) led to the expansion of Roman military power and political sovereignty beyond the Italian peninsula into both the western and eastern Mediterranean. This expansion, which was virtually complete by 30 bce, brought wealth to the citizens of Rome and expanded the opportunities of the Roman elite to exercise political power as civil and military authorities in the newly acquired provinces.
The expansion also led to the breakdown of the republic’s institutions. As Rome’s military commitments expanded, the willingness of its propertied citizens to serve in long campaigns far afield declined. In 107 bce military service was made voluntary, and propertyless citizens (the proletarii) were allowed to enlist. Fighting under a successful general, the poor could achieve at least the possibility of upward economic mobility. Goods distributed by commanding officers to their men included salaries, plunder, gifts, and plots of land parceled out from conquered colonies. Not surprisingly, loyalty to the general replaced loyalty to the state.
As a result, the first century bce was marked by a succession of civil wars between Roman generals competing for dictatorial power over the state. These wars culminated in the conflicts between Julius Caesar and Pompey (49–46 bce) and Marc Antony and Octavian (33–30 bce). These wars were fought across the entire expanse of Rome’s empire, from Spain through Italy to Egypt, and ended in the permanent imposition of monarchic rule upon the Roman state.
After Julius Caesar had defeated the last supporters of his rival Pompey, the Senate embraced the ensuing peace and made Caesar dictator for life in 44 bce. Although he was assassinated two months later by patrician conspirators claiming they were defending the constitution of the republic, Caesar’s popularity among his soldiers ensured that the period of uncertainty led not to a restoration of rule by the Senate and popular assemblies but rather to a power struggle between two claimants to the command of Caesar’s troops and political authority: his lieutenant Marc Antony and his adopted son Octavian.
Open war between the rivals broke out in 33 bce and ended with the suicide of Marc Antony and his ally Cleopatra, whereas Octavian returned to Rome in triumph. In 28 bce the Senate appointed him its princeps (leader) and in 27 bce gave him the new title of “Augustus,” signifying his supreme authority over the state. These new titles in effect created for Augustus (as Octavian was henceforth addressed) the constitutional power of dictator for life. Although the old institutions and offices of the republic remained in place, Augustus now wielded a permanent sovereignty over all aspects of the state, including the Senate, consuls, assemblies, tribunes, and armies. When he died in 14 ce, Augustus was able to pass on his office to his designated successor, Tiberius (reigned 14–37 ce).
The form of government established by Augustus is known as the “principate.” Although the legal authority of the princeps was absolute, Augustus and his successors allowed much of the day-to-day administration of the state and its empire to remain in the hands of officers and institutions carried over from the republican period. Under the first two dynasties, the Julio-Claudians (14–68 ce) and the Flavians (69–96 ce), periods of apparent instability did not prevent the system established by Augustus from remaining intact. Despite the excesses attributed by contemporaries to Caligula (reigned 37–41 ce), Nero (reigned 54–68 ce), and Domitian (reigned 81–96 ce), the administrative structures of the principate continued to function in an orderly and effective manner. When a civil war broke out at the end of Nero’s reign, each of the rivals claimed the title of “Augustus.” No one considered the possibility of eradicating that office.
Overall, the first two centuries of the principate brought the Roman Empire the benefits of peace and material prosperity, reaching an apex under the reigns of Trajan (98–117 ce), Hadrian (117–138 ce), Antoninus Pius (138–161 ce), and Marcus Aurelius (161–180 ce). These emperors ruled over a population estimated at 50 to 70 million, linked together by roads, aqueducts, maritime travel and trade, and a shared imperial culture. Despite the era of general peace and prosperity, a significant portion of that population was decimated by the Antonine plague (165–180 ce), which occurred during the reign of Marcus Aurelius and is reputedly responsible for his death via some form of infection while at his army camp. Named after his family name, Antoninus, and also known as the Plague of Galen after the prominent Roman physician who documented the pandemic, it was brought back to Rome by soldiers returning from campaigns around Seleucia in the Near East. Infecting significant numbers of people across and beyond the boundaries of the empire, the plague is estimated to have wiped out up to one-third of the population in some areas. By some estimates the plague was responsible for as many as two thousand deaths a day and ultimately caused the deaths of millions of Romans. With a mortality rate as high as ten percent, the Roman army was inevitably and severely affected by the plague. Some see the devastating results of the Antonine plagues as a key turning point in the rise and fall of the Roman Empire.
The two universal languages of the empire were Latin and Greek, and under the principate a large number of the empire’s inhabitants spoke both. Much of the inspiration for Roman artistic and literary forms derived from Greek models, whose influence became paramount as soon as Rome first established its military dominance over Greece. The first full blossoming of Rome’s cultural achievements coincided with the republic’s unraveling during the first century bce. Many of the finest surviving fruits of Roman literature and architecture, however, were produced under the principate. If the late republic can claim the historian Sallust, the poet Catullus, and the statesman Cicero, the principate can claim, among others, the poets Virgil, Ovid, Horace, and Juvenal; the historians Livy and Tacitus; the philosopher and dramatist Seneca; the essayist and biographer Plutarch; the medical theorist Galen; the astronomer Ptolemy; and the architects of the Colosseum and Pantheon. But if the prosperity of the empire derived in large part from the Pax Romana (the peace the Romans succeeded in imposing on the Mediterranean world and used as justification for their imperialism), it also relied heavily on slave labor, a mainstay of the Roman economy since the conquests of the third and second centuries bce.
On 31 December 192 ce, Marcus Aurelius’s son and successor Commodus (reigned 180–192 ce) was murdered in a palace coup. He was the first emperor to meet a violent end since Domitian, who was assassinated in 96 ce. Claiming to be the incarnation of Hercules and the most skilled of gladiators, Commodus had emphasized the role of emperor as warrior above any other function of the office. All of the contenders in the subsequent civil war legitimized their claim to the imperial throne through acclamation by the empire’s soldiers, each being supported by different contingents of the Roman army. The ultimate victor, Septimus Severus (reigned 193–211 ce), secured his title by presenting himself to the people as a military conqueror. The institutions of the principate gave way to an empire ruled and fought over by competing generals. The results were a marked economic decline, political chaos, and a serious destabilization of the empire’s borders.
With military victory now the sole means of legitimating imperial authority, the emperors became substantially more bellicose. Warfare became the norm with the advent of sustained attacks on the empire’s borders along several fronts, most threateningly by Germanic peoples along the north and Persians along the east. An emperor’s defeat on the battlefield was likely to lead to his assassination, and a victory won by one of his generals proved almost as dangerous. The situation was not conducive to maintaining internal order or external defenses, and both suffered. Among the threats to Rome’s territorial integrity, the most dramatic was the revolt of Zenobia, queen of Palmyra. She managed to rule over Syria, Anatolia, and Egypt for several years before being defeated by the emperor Aurelian in 272 ce. The years between 211 ce and 284 ce included a succession of some twenty emperors, averaging four years per reign.
The situation stabilized under the rule of Diocletian (reigned 284–305 ce). Although he came to power as yet another military strongman, he managed to reorganize and thereby stabilize the structure of the Roman state. The most enduring of his reforms included the division of the empire into eastern (Greek-speaking) and western (Latin-speaking) administrative units, the introduction of centralized planning to the Roman economy, and the dramatic expansion of the imperial household staff into a civil bureaucracy that supplanted the obsolete republican magistracies and served as an effective counterweight to the power of the army. Constantine (reigned 306–337 ce) cemented the success of Diocletian’s reforms with two revolutionary innovations of his own. The founding of the city of Constantinople (modern Istanbul, Turkey) provided the eastern half of the empire with a capital that possessed legal and symbolic parity with Rome. The transformation of Christianity, in turn, from a persecuted sect to the object of imperial patronage endowed the emperors with a new source of legitimacy independent of both the army and the civil bureaucracy. The association of the one God with the one emperor provided an effective justification for the divinely instituted authority of imperial rule.
The reforms of Diocletian and Constantine, which transformed the Roman state legally and institutionally into an absolute monarchy, also brought about cultural revival and economic recovery to a society still suffering from the devastations of the Antonine plague. The theologian Augustine of Hippo, the historian Ammianus Marcellinus, the villas whose archaeological remains dot all the former territories of the empire, the numerous monumental Christian churches that survive intact, and the codifications of Roman law under Theodosius II (reigned 408–450 ce) and Justinian (reigned 527–565 ce) are just a few prominent examples of the artistic, literary, and intellectual accomplishments produced by both pagans and Christians between the fourth and sixth centuries.
In spite of these achievements, the same period included a political fragmentation conventionally labeled “the fall of Rome.” The organization of the empire into administrative halves created, alongside the political divide, an increasingly pronounced linguistic and cultural separation between the Greek east and the Latin west. When a new wave of external invasions commenced during the final decades of the fourth century, the Eastern Roman Empire centered in Constantinople managed to survive. The Western Roman Empire, however, lost its territorial integrity and legal identity during the 400s as Germanic leaders established new kingdoms in Italy, France, England, and North Africa. However, historians have come to prefer to describe this process as a “transformation” rather than a “fall.” The material and intellectual culture of these new kingdoms remained recognizably that of Rome, while their kings borrowed their political ideology, symbols and rituals of rule, and administrative techniques from the Roman emperors. Furthermore many of these kings either descended from or themselves had been generals in the service of the Roman army (which had relied increasingly on foreign auxiliaries and military officers since the third century). Finally, when the Western Roman Empire ceased to exist as a separate entity after the deposition of Romulus Augustulus in 476 ce, the emperor in Constantinople simply claimed legal authority over the entire Roman imperium for himself and his successors.
The Eastern Roman Empire survived as a sovereign state until 1453, having in the meantime provided a prototype for the revival by the Frankish king Charlemagne of a Roman Empire that endured in western Europe from 800 to 1806. After Constantinople fell, Russian czars and Ottoman sultans each proclaimed themselves successors to the Roman emperors. Their states survived into the twentieth century and thus, in a way, so did the Roman Empire. More significantly, the ideas, symbols, institutions, and laws of that empire have provided models for many other states and governing institutions through the centuries and continue to do so today. This partially explains why politicians, journalists, and scholars can productively use the events of Roman history to illuminate current social and political concerns.
History is little more than the register of the crimes, follies, and misfortunes of mankind.Edward Gibbon (1737–1794)