Augustus was the first Roman emperor and the founder of the political system known as the Principate. He ruled from 27 BC until his death in AD 14, bringing an end to the civil wars that had destabilised Rome for generations. Augustus avoided presenting himself as a king or dictator. Instead, he combined Republican offices, military command, religious authority and personal prestige to create a monarchy that appeared to preserve the Roman Republic.
Octavian, Heir of Caesar
Augustus was born Gaius Octavius on 23 September 63 BC. He came from a prosperous Italian family but did not initially belong to the highest level of Rome’s political elite.
His maternal great-uncle was Julius Caesar. When Caesar was assassinated in 44 BC, his will revealed that he had adopted Octavius as his son and named him his principal heir.
The eighteen-year-old accepted the inheritance and took Caesar’s name. Modern historians usually call him Octavian during the period between his adoption and his receipt of the title Augustus.
Caesar’s name gave Octavian access to political influence, financial resources and the loyalty of veterans. Mark Antony, one of Caesar’s leading supporters, initially underestimated the young heir and attempted to control Caesar’s legacy himself.
The Struggle for Power
Octavian recruited soldiers from among Caesar’s veterans and entered Roman politics with military support. He temporarily cooperated with the Senate and the orator Cicero against Mark Antony.
In 43 BC, Octavian marched on Rome and secured election as consul. He then formed an alliance with Antony and Marcus Aemilius Lepidus.
Their partnership was formally established as the Second Triumvirate. Unlike the earlier informal alliance of Caesar, Pompey and Crassus, the triumvirs received legal authority to reorganise the Roman state.
They introduced proscriptions in which political enemies were declared outlaws, killed and stripped of their property. Cicero was among the most famous victims.
In 42 BC, the forces of Octavian and Antony defeated Caesar’s assassins, Brutus and Cassius, at the Battle of Philippi. The victors then divided the Roman territories among themselves.
Victory Over Antony and Cleopatra
The alliance between the triumvirs gradually collapsed. Lepidus was removed from power, leaving Octavian in control of the western provinces and Antony dominant in the east.
Antony’s partnership with Cleopatra VII of Egypt allowed Octavian to portray his rival as a Roman corrupted by a foreign queen. Octavian presented the conflict as a defence of Italy and Roman tradition.
In 31 BC, Octavian’s forces defeated Antony and Cleopatra at the naval Battle of Actium. His commander Marcus Vipsanius Agrippa played a decisive role in the campaign.
Antony and Cleopatra returned to Egypt and died in 30 BC as Octavian’s forces captured Alexandria. Egypt became a Roman province under Octavian’s direct control.
Octavian was now the sole ruler of the Roman world. The challenge before him was to transform military victory into a stable and acceptable form of government.
The Problem of One-Man Rule
The Romans had a deep cultural hostility towards kingship. Their political traditions celebrated the expulsion of Rome’s last king and the establishment of the Republic.
Julius Caesar’s permanent dictatorship had ended in assassination because senators feared that he intended to become a monarch. Octavian understood that openly claiming royal power would provoke resistance.
He therefore preserved Republican institutions such as the Senate, consulship and popular assemblies. Magistrates continued to be elected, laws continued to be passed and senators continued to debate public affairs.
Behind these institutions, however, Octavian controlled the armies, the most important provinces and the resources of Egypt. No rival possessed enough military or financial power to challenge him.
The Meaning of the Principate
The system created by Augustus is known as the Principate. The name comes from princeps, meaning first citizen or leading man.
Princeps had Republican associations and did not openly suggest monarchy. Augustus presented himself as the foremost member of the Roman political community rather than as a king ruling over subjects.
The Principate preserved the language and appearance of Republican government while concentrating decisive authority in the emperor. Its success depended upon maintaining a careful balance between monarchical power and traditional political forms.
The First Settlement of 27 BC
In January 27 BC, Octavian formally returned his extraordinary powers and provinces to the Senate and Roman people. This carefully arranged act suggested that the civil wars had ended and normal Republican government had been restored.
The Senate responded by asking him to retain control of several important provinces, including Spain, Gaul and Syria. These territories contained most of the Roman legions.
His provincial command was initially granted for ten years, creating the appearance that it was temporary. In practice, it was repeatedly renewed.
The remaining provinces were assigned to governors chosen through senatorial procedures. This division created what are commonly called imperial and senatorial provinces.
The arrangement allowed Augustus to claim that he shared authority with the Senate while ensuring that the majority of the army remained under his command.
The Name Augustus
As part of the settlement, the Senate granted Octavian the name Augustus. The title carried religious and dignified associations and suggested that its holder possessed exceptional authority.
He also received civic honours, including a laurel wreath placed at the entrance to his home and a civic crown associated with saving Roman lives.
A golden shield was displayed in the Senate house celebrating his courage, mercy, justice and devotion. These honours helped define the qualities Augustus wanted connected with his rule.
The name Augustus gradually became inseparable from the office of emperor. It was later adopted as a title by his successors.
The Second Settlement of 23 BC
Augustus continued to hold the consulship every year after 31 BC. This gave him formal authority in Rome but prevented other ambitious senators from reaching the highest office.
In 23 BC, he resigned the annual consulship and reorganised the constitutional basis of his position. The change made more consulships available to members of the aristocracy.
Augustus received tribunician power for life. This gave him the authority associated with the tribunes of the plebs without requiring him to hold the office itself.
Tribunician power allowed him to summon the Senate and assemblies, propose legislation and veto the actions of other magistrates. It also presented him as the protector of ordinary Roman citizens.
Augustus also held superior proconsular authority, commonly described as greater imperium. This allowed him to intervene in provincial affairs and outranked the authority of other governors when necessary.
The settlement gave Augustus immense practical power while allowing Republican offices to continue around him.
Auctoritas and Personal Prestige
Augustus claimed that he exceeded other Romans in auctoritas rather than in the formal power attached to office. Auctoritas referred to prestige, influence and recognised personal standing.
His auctoritas came from military victory, wealth, religious honours, family connections and his position as Caesar’s adopted son. It allowed him to guide decisions without always issuing direct commands.
This language concealed the unequal reality of the Principate. Augustus possessed control over armies and provinces that no ordinary senator could match.
Nevertheless, presenting his authority as personal influence helped preserve the dignity of the Senate and reduced the appearance of arbitrary rule.
The Senate Under Augustus
Augustus treated the Senate as an important partner in government, but he also reshaped its membership and limited its independence.
The Senate had expanded greatly during the final decades of the Republic. Augustus reviewed its membership and removed individuals whom he considered unsuitable.
He established property qualifications and attempted to restore the Senate’s social prestige. He also encouraged senators to attend meetings and participate in public administration.
Senators continued to govern provinces, command some armies and hold important magistracies. Their careers still brought status and influence.
However, the Senate could not challenge Augustus’s control of the military. Its authority operated within boundaries established by the princeps.
The Popular Assemblies
Roman citizens continued to meet in assemblies and elect magistrates during much of Augustus’s reign. The forms of popular participation did not immediately disappear.
Augustus used recommendations, influence and control of candidate lists to shape election results. Few candidates could succeed without his approval.
Over time, meaningful electoral competition declined. Political advancement increasingly depended upon service to the emperor rather than independent popular support.
The assemblies gradually lost much of their political significance, although the Roman people remained important as an audience for ceremonies, games and public announcements.
Control of the Army
Military control formed the essential foundation of Augustus’s power. He commanded most of Rome’s legions through governors and officers who served as his representatives.
After the civil wars, Augustus reduced the enormous number of legions and created a smaller permanent army. Approximately twenty-eight legions remained for much of his reign, although the number changed after military disasters.
Legionaries became long-service professional soldiers. Most were Roman citizens who served for many years in exchange for regular pay and a retirement reward.
Non-citizen soldiers served in auxiliary units that provided cavalry, archers and specialised troops. After completing their service, auxiliary soldiers could receive Roman citizenship.
This system created a standing military establishment capable of defending frontiers and supporting Roman expansion.
Veterans and Military Settlements
Veteran settlement had caused serious unrest during the civil wars because land was sometimes confiscated from Italian communities. Augustus needed a more stable way to reward retiring soldiers.
He increasingly provided cash payments rather than relying entirely upon land confiscation. In AD 6, he established a military treasury to fund retirement benefits.
The treasury received income from new taxes, including a tax on inheritances. Augustus also contributed a large amount of his own wealth.
By making the state responsible for veterans, Augustus reduced the dependence of soldiers on individual commanders. Even so, the army’s loyalty remained closely connected to the emperor.
The Praetorian Guard
Augustus organised the Praetorian Guard as an elite force responsible for protecting him and maintaining security in Italy.
The Praetorians received better pay and shorter terms of service than ordinary legionaries. Some units were stationed near Rome, although their permanent concentration in a single camp occurred under a later emperor.
The Guard symbolised the military foundation of imperial authority. Under later emperors, it became an influential political force capable of supporting or removing rulers.
Administration of the Provinces
Augustus reorganised provincial government to improve stability and reduce abuses. Governors in imperial provinces served as his representatives and were accountable to him.
Senatorial provinces continued to be governed by proconsuls. These provinces generally contained fewer troops and were considered more peaceful.
Egypt held a unique position. It was governed by an equestrian prefect appointed by Augustus, and senators could not enter without permission.
Control of Egypt gave Augustus access to immense wealth and a major source of grain. Its special status prevented a powerful senator from using the province as a base for rebellion.
The Equestrian Order
Augustus expanded the administrative role of the equestrian order. Equestrians were wealthy Romans who ranked below senators but possessed considerable social prestige.
They served as financial officials, military commanders and governors of certain provinces. Important positions in Egypt and the Praetorian Guard were entrusted to equestrians.
By employing both senators and equestrians, Augustus increased the number of capable officials available to administer the empire. He also prevented the senatorial class from monopolising every important appointment.
Taxation and Financial Reform
Rome’s provinces supplied taxes that supported the army, administration and public building programme. Under the Republic, private tax collectors had often exploited provincial communities.
Augustus introduced more regular assessments and expanded the use of official censuses. Accurate information about land, population and property made taxation more predictable.
Local communities continued to collect many taxes, and abuses did not disappear. Nevertheless, imperial supervision could provide greater stability than the short-term provincial commands of the late Republic.
Augustus distinguished between the traditional state treasury and funds connected more directly to imperial administration. His vast personal wealth often supported public expenses, making the boundary between state and ruler increasingly unclear.
Rome’s Grain Supply
Providing food for Rome’s large population was one of the government’s most important responsibilities. Disruptions to the grain supply could cause unrest and damage the ruler’s popularity.
Augustus improved the organisation of grain distribution and took personal responsibility during shortages. Egypt and North Africa became essential sources of imported grain.
A permanent official system for supervising the supply developed under the Principate. Reliable access to food helped maintain stability in the capital.
Building a New Rome
Augustus transformed the appearance of Rome through an extensive programme of construction and restoration. He repaired temples, built public spaces and encouraged his supporters to sponsor monuments.
His Forum of Augustus contained the Temple of Mars Ultor, or Mars the Avenger. The temple commemorated the defeat of Caesar’s assassins and linked Augustus’s personal victory with Roman religion.
He constructed or restored theatres, porticoes, roads, aqueducts and religious buildings. Agrippa contributed major projects, including the original Pantheon and public baths.
Augustus later claimed that he had found Rome built of brick and left it clothed in marble. The statement was an exaggeration, but it expressed the scale and ambition of the transformation.
The Division of Rome
Augustus reorganised the city into administrative regions and neighbourhoods. Local officials helped supervise streets, fire prevention and community religious practices.
Rome was vulnerable to fires, floods and building collapses. Augustus introduced organised groups to improve public safety, although later emperors developed these services further.
Local shrines incorporated the worship of the household spirits of Augustus. This connected neighbourhood identity with loyalty to the new political order.
The Augustan Peace
Augustus promoted his reign as a restoration of peace after decades of civil war. The phrase Pax Augusta described the order created by his victories and government.
The closing of the doors of the Temple of Janus symbolised the absence of war throughout the Roman world. Augustus emphasised that this rare ceremony occurred several times during his rule.
The peace was real for many inhabitants of Italy and the established provinces. Roads became safer, piracy was reduced and political stability supported trade.
However, the Augustan peace depended upon military force. Roman armies continued campaigning along the frontiers, and conquered peoples experienced violence, enslavement and taxation.
The Ara Pacis
The Senate commissioned the Ara Pacis, or Altar of Augustan Peace, to commemorate Augustus’s return from the western provinces. It was dedicated in 9 BC.
The monument combined images of prosperity, religion, family and political leadership. Processional scenes depicted Augustus, priests and members of the imperial household.
Its imagery associated the new regime with fertility, stability and divine favour. Peace was presented not simply as the absence of war but as a condition allowing families, agriculture and religious life to flourish.
Religion and the Restoration of Tradition
Augustus claimed to restore traditional Roman religion. He repaired neglected temples, revived ceremonies and filled priestly offices.
He became a member of several priestly colleges and eventually assumed the position of pontifex maximus in 12 BC. This made him the leading figure in Roman public religion.
Augustus presented Rome’s earlier troubles as partly caused by moral and religious decline. The revival of worship therefore supported his claim to have restored the Republic.
Religion also gave sacred meaning to his authority. Augustus avoided becoming an official god at Rome during his lifetime, but his connection with the divine was repeatedly emphasised.
The Son of a God
After Julius Caesar’s death, the Senate declared him divine. Octavian could therefore call himself the son of a god.
A comet appeared during games held in Caesar’s honour in 44 BC. Octavian promoted it as the soul of the deified Caesar rising to heaven.
Coins, statues and monuments connected Augustus with Apollo, Mars and other gods. These associations suggested divine support without always claiming that Augustus himself was a god.
In eastern provinces, traditions of ruler worship made direct honours more acceptable. Temples were established for Rome and Augustus, often with his approval.
Moral Legislation
Augustus attempted to regulate marriage, childbirth and sexual conduct through legislation. He believed that Rome’s governing classes were failing to marry and produce enough legitimate children.
His laws encouraged marriage and rewarded parents with several children. Unmarried and childless citizens could face restrictions concerning inheritance.
Adultery became a public criminal offence rather than only a private family matter. Male guardians were given specific powers and responsibilities when dealing with adultery.
The legislation was unpopular and difficult to enforce. It also exposed contradictions between Augustus’s public moral programme and the behaviour of members of his own family.
The Exile of Julia
Augustus’s daughter Julia was central to his dynastic plans. Her marriages connected potential successors to the imperial family.
In 2 BC, Augustus exiled Julia after accusations of adultery and scandalous behaviour. Her alleged conduct directly violated the moral standards promoted by her father.
The punishment was personally and politically painful. Augustus restricted her living conditions and removed her from public life.
Julia’s exile demonstrated that the imperial household had become part of public government. The private behaviour of the ruler’s family could affect the legitimacy of the entire regime.
Marriage and Family Alliances
Augustus married Livia Drusilla in 38 BC. Livia came from a distinguished aristocratic family and became his trusted companion for more than five decades.
They had no children together, but Livia had two sons from her previous marriage, Tiberius and Drusus. Both became important military and political figures.
Augustus used marriage and adoption to connect possible successors to his family. These arrangements were repeatedly disrupted by illness and premature death.
Marcellus and Agrippa
Augustus initially promoted his nephew and son-in-law Marcellus as a possible successor. Marcellus died in 23 BC while still a young man.
Marcus Agrippa then became increasingly important. He was Augustus’s closest military partner and had played a decisive role at Actium.
Agrippa married Julia and received powers that placed him close to Augustus in political status. Their sons Gaius and Lucius Caesar were adopted by Augustus.
Agrippa died in 12 BC, depriving Augustus of his most capable and trusted colleague.
Gaius and Lucius Caesar
Augustus presented Gaius and Lucius as the future leaders of the Roman state. They received honours, public offices and military responsibilities at unusually young ages.
Lucius died in AD 2 while travelling to Spain. Gaius suffered a wound during service in the east and died in AD 4.
Their deaths forced Augustus to reconsider the succession. The problem revealed a weakness within the Principate because no formal law determined how the powers of the princeps should pass to another person.
Tiberius Becomes the Heir
Augustus eventually adopted Livia’s elder son Tiberius in AD 4. Tiberius was an experienced commander who had served successfully in Germany, the Balkans and the eastern provinces.
As part of the arrangement, Tiberius adopted Germanicus, the son of his late brother Drusus. This created another generation of potential successors.
Tiberius received tribunician power and shared important responsibilities with Augustus. By the final years of the reign, he was clearly positioned to take control.
The succession remained officially framed as the transfer of Republican powers rather than the inheritance of a crown. In practice, Augustus had established a dynasty.
Expansion in the West
Roman armies continued expanding during Augustus’s reign. Campaigns completed the conquest of northern Spain and brought the Alpine regions under Roman control.
Augustus’s stepsons Tiberius and Drusus led operations that extended Roman influence towards the Danube and Rhine. New provinces and military zones strengthened the northern frontier.
Roads, forts and settlements supported the movement of armies and officials. Conquest was followed by taxation, recruitment and gradual cultural exchange.
Diplomacy With Parthia
The Parthian Empire remained Rome’s most powerful eastern rival. Roman standards captured during earlier defeats, especially the Battle of Carrhae, had become symbols of humiliation.
In 20 BC, Augustus secured the return of the standards and surviving prisoners through negotiation. He presented the diplomatic agreement as if it were a major military victory.
The recovered standards were placed in the Temple of Mars Ultor. Coins and monuments celebrated their return as proof of Augustus’s ability to restore Roman honour.
The Disaster in Germany
Augustus attempted to extend Roman control beyond the Rhine into Germania. Roman commanders conducted campaigns, built forts and introduced provincial administration.
In AD 9, an alliance of Germanic peoples led by Arminius ambushed the Roman governor Publius Quinctilius Varus in the Teutoburg Forest.
Three Roman legions were destroyed along with their auxiliary forces and civilian followers. The lost legions were the Seventeenth, Eighteenth and Nineteenth.
The defeat shocked Augustus and ended immediate plans for permanent expansion to the River Elbe. Rome later conducted punitive campaigns but generally maintained the Rhine as its principal frontier.
Literature and Augustan Culture
The reign of Augustus produced some of the most influential works of Latin literature. Poets and historians explored Rome’s past, civil conflict and imperial destiny.
Virgil’s Aeneid connected Augustus’s Rome with the legendary Trojan hero Aeneas. The poem celebrated Roman achievement while also reflecting on the suffering caused by war and empire.
Horace wrote about peace, morality, friendship and public responsibility. Livy composed an extensive history of Rome from its legendary foundation.
Ovid offered a more playful and sometimes challenging voice. Augustus eventually exiled him to Tomis on the Black Sea for reasons the poet described only as a poem and a mistake.
Writers were not simply government officials producing propaganda. Their works could support the Augustan order while also expressing uncertainty about power, violence and the cost of Rome’s success.
Images and Imperial Communication
Augustus used coins, statues, buildings and public ceremonies to communicate throughout the empire. These images reached audiences who would never see him in person.
Portraits presented him with an idealised and youthful appearance even as he grew older. The unchanging image suggested stability, energy and timeless authority.
The statue commonly known as Augustus of Prima Porta depicted him as a victorious commander addressing troops. Its decorated breastplate celebrated diplomatic and military success.
Other images showed him as a priest with his head covered. Together, these portraits presented Augustus as commander, statesman, religious leader and bringer of peace.
The Res Gestae
Near the end of his life, Augustus prepared an account of his achievements known as the Res Gestae. Copies were displayed in Rome and in provinces across the empire.
The text listed his offices, honours, public spending, military victories and services to the Roman people. It emphasised generosity and constitutional restraint.
Augustus claimed to have transferred the Republic from his own power to the control of the Senate and people. He described himself as surpassing others in influence rather than official authority.
The document is invaluable evidence, but it presents a carefully constructed version of his career. It says little about the proscriptions, civil-war violence or coercion that made his position possible.
Opposition and Conspiracy
Augustus’s regime was more stable than the late Republic, but it did not eliminate opposition. Several alleged conspiracies developed during his long rule.
Some aristocrats resented the loss of political independence, while others competed for access to imperial favour. Augustus sometimes responded with trials, exile or execution.
His policy of clemency coexisted with firm action against perceived threats. The peaceful image of the Principate rested upon effective control of political opponents.
Everyday Government
Augustus devoted considerable attention to administration. He received petitions, judged disputes, corresponded with governors and supervised appointments.
He created advisory groups to help prepare business for the Senate. Members of his household also assisted with correspondence and financial management.
The imperial administration remained small by modern standards. Local councils and elites performed much of the daily work of government across the provinces.
The Principate succeeded partly because it cooperated with existing communities rather than attempting to administer every region directly from Rome.
The Position of Italy
Italy occupied a privileged place within the Augustan system. Its inhabitants possessed Roman citizenship, and the peninsula was not governed as an ordinary province.
Augustus improved roads and communications and divided Italy into administrative regions. These measures assisted censuses, taxation and the management of public resources.
Italian communities retained local governments while becoming more closely integrated into the Roman state.
Life in the Provinces
For provincial inhabitants, Augustan government could bring both stability and exploitation. Peaceful conditions encouraged trade, construction and urban development.
Local elites gained status by serving on councils, sponsoring buildings and supporting imperial ceremonies. Cooperation with Rome could provide citizenship and opportunities for advancement.
At the same time, provinces paid taxes and supplied resources to maintain the imperial system. Resistance could bring severe military punishment.
The effects of Roman rule varied greatly between regions. The Principate combined local autonomy with ultimate obedience to the emperor.
Augustus and Slavery
Roman society under Augustus depended heavily upon enslaved labour. Enslaved people worked in households, agriculture, mining, crafts and administration.
Augustus introduced laws regulating the freeing of enslaved people and restricting some grants of citizenship. These measures reflected concern about social order and the rapid growth of the freed population.
Freed people could become economically successful, but they continued to owe duties to their former owners. Their children were normally born free and could enter wider Roman society.
The Limits of Augustan Restoration
Augustus repeatedly claimed that he had restored the Republic. He revived traditions, repaired temples and allowed Republican offices to continue.
Yet the political system had been fundamentally transformed. No consul, senator or popular assembly could match his control of armies, provinces and wealth.
The restoration was therefore both real and deceptive. Augustus restored order, religious institutions and regular administration, but he did not restore the competitive independence of the old Republic.
He created a new system that borrowed Republican language to make permanent personal rule acceptable.
The Death of Augustus
Augustus died at Nola in southern Italy on 19 August AD 14. He was seventy-five years old and had dominated Roman political life for more than four decades.
Ancient tradition attributed several memorable final statements to him, including a request that those present applaud if he had played his part well. The exact words are uncertain.
His body was carried to Rome and cremated in a magnificent public funeral. His ashes were placed in the great mausoleum he had constructed for his family.
The Senate declared Augustus a god. Temples and priests were established to maintain his worship.
The Accession of Tiberius
Tiberius succeeded Augustus without a major civil war. The Senate formally granted him the powers needed to govern, preserving the appearance of constitutional procedure.
His accession demonstrated that the Principate could survive the death of its founder. It also confirmed that Rome had entered a dynastic political system.
Tiberius inherited Augustus’s armies, provinces and institutions, but he could not inherit his predecessor’s unique prestige. Every later emperor had to define his relationship with the Augustan model.
The Success of the Principate
Augustus succeeded because he combined overwhelming power with political restraint in its presentation. He understood that Roman aristocrats valued honours, offices and the appearance of participation.
He allowed the Senate to retain dignity while ensuring that it could not threaten his position. He rewarded soldiers while creating permanent systems for service and retirement.
He connected his authority with peace, religion, family and Roman tradition. Monuments and literature presented his rule as the fulfilment of history rather than the result of civil-war victory.
His long reign allowed an entire generation to grow up without experiencing the political competition of the independent Republic. What had once seemed extraordinary gradually became normal.
The Cost of Stability
The Principate ended repeated civil wars and gave the Mediterranean world a more predictable government. It improved provincial administration and established institutions that endured for centuries.
This stability came at the cost of political freedom among Rome’s governing elite. Elections lost importance, open opposition became dangerous and military power determined ultimate authority.
The system also depended heavily upon the character and competence of the emperor. A strong ruler could provide effective government, while a weak or destructive ruler could misuse the same concentration of power.
The Legacy of Augustus
Augustus transformed Rome more completely than any earlier leader. He inherited a Republic damaged by civil war and left behind an imperial monarchy concealed within Republican traditions.
His reforms shaped the army, provinces, taxation, religion and political institutions of the Roman Empire. Later emperors continued to use his titles and present themselves as heirs to his achievements.
The name Caesar became a title for emperors, while Augustus remained one of the highest expressions of imperial authority. His model influenced Roman government for centuries.
Augustus was both a restorer and a revolutionary. He restored peace and traditional ceremonies, but he also created a political system that permanently altered the meaning of Roman citizenship and public office.
The Principate endured because it allowed Rome to accept monarchy without openly admitting that the Republic had ended. Augustus’s greatest political achievement was not simply acquiring supreme power, but making that power appear lawful, necessary and compatible with Roman tradition.