"Octavian" redirects here. For other uses of "Octavian", see Octavian (disambiguation). For other uses of "Augustus", see Augustus (disambiguation).

Gaius Julius Caesar Augustus (23 September 63 BC – 19 August AD 14) was the first emperor of the Roman Empire, which he ruled alone from 27 BC until his death in AD 14.

Born Gaius Octavius Thurinus, he was adopted by his great-uncle Julius Caesar in 44 BC, and between then and 27 BC was officially named Gaius Julius Caesar. In 27 BC the Senate awarded him the honorific Augustus, and thus consequently he was Gaius Julius Caesar Augustus.^{[note 2]} Because of the various names he bore, it is common to call him Octavius when referring to events between 63 and 44 BC, Octavian (or Octavianus) when referring to events between 44 and 27 BC, and Augustus when referring to events after 27 BC. In Greek sources, Augustus is known as Ὀκτάβιος (Octavius), Καῖσαρ (Caesar), Αὔγουστος (Augustus), or Σεβαστός (Sebastos), depending on context.

The young Octavius came into his inheritance after Caesar's assassination in 44 BC. In 43 BC, Octavian joined forces with Mark Antony and Marcus Aemilius Lepidus in a military dictatorship known as the Second Triumvirate. As a triumvir, Octavian ruled Rome and many of its provinces^{[note 3]} as an autocrat, seizing consular power after the deaths of the consuls Hirtius and Pansa and having himself perpetually re-elected. The triumvirate was eventually torn apart under the competing ambitions of its rulers: Lepidus was driven into exile, and Antony committed suicide following his defeat at the Battle of Actium by the fleet of Octavian commanded by Agrippa in 31 BC.

After the demise of the Second Triumvirate, Octavian restored the outward facade of the Roman Republic, with governmental power vested in the Roman Senate, but in practice retained his autocratic power. It took several years to determine the exact framework by which a formally republican state could be led by a sole ruler; the result became known as the Roman Empire. The emperorship was never an office like the Roman dictatorship which Caesar and Sulla had held before him; indeed, he declined it when the Roman populace "entreated him to take on the dictatorship". By law, Augustus held a collection of powers granted to him for life by the Senate, including those of tribune of the plebs and censor. He was consul until 23 BC. His substantive power stemmed from financial success and resources gained in conquest, the building of patronage relationships throughout the Empire, the loyalty of many military soldiers and veterans, the authority of the many honors granted by the Senate, and the respect of the people. Augustus' control over the majority of Rome's legions established an armed threat that could be used against the Senate, allowing him to coerce the Senate's decisions. With his ability to eliminate senatorial opposition by means of arms, the Senate became docile towards his paramount position. His rule through patronage, military power, and accumulation of the offices of the defunct Republic became the model for all later imperial government.

The rule of Augustus initiated an era of relative peace known as the Pax Romana, or Roman peace. Despite continuous frontier wars, and one year-long civil war over the imperial succession, the Mediterranean world remained at peace for more than two centuries. Augustus expanded the Roman Empire, secured its boundaries with client states, and made peace with Parthia through diplomacy. He reformed the Roman system of taxation, developed networks of roads with an official courier system, established a standing army (and a small navy), established the Praetorian Guard, and created official police and fire-fighting forces for Rome. Much of the city was rebuilt under Augustus; and he wrote a record of his own accomplishments, known as the Res Gestae Divi Augusti, which has survived. Upon his death in AD 14, Augustus was declared a god by the Senate, to be worshipped by the Romans. His names Augustus and Caesar were adopted by every subsequent emperor, and the month of Sextilis was officially renamed August in his honour. He was succeeded by his stepson and son-in-law, Tiberius.

While his paternal family was from the town of Velitrae, about 25 miles from Rome, Augustus was born in the city of Rome on 23 September 63 BC. He was born at Ox Heads, which was a small property on the Palatine Hill, very close to the Roman Forum. An astrologer had given a warning to his father. However, his father decided to keep the child despite the warning (rather than leave the child in the open to be eaten by dogs). He was given the name Gaius Octavius Thurinus, his cognomen possibly commemorating his father's victory at Thurii over a rebellious band of slaves. Due to the crowded nature of Rome at the time, Octavius was taken to his father's home village at Velitrae to be raised. Octavius only mentions his father's equestrian family briefly in his memoirs. His paternal great-grandfather was a military tribune in Sicily during the Second Punic War. His grandfather had served in several local political offices. His father, also named Gaius Octavius, had been governor of Macedonia. His mother Atia was the niece of Julius Caesar.

Since Octavius' father was a plebeian, Octavius himself was a plebeian, despite the fact that his mother, being Julius Caesar's niece, was a patrician. Octavius gained patrician status when he was adopted by Julius Caesar in 44 BC.

In 59 BC, when he was four years old, his father died. His mother married a former governor of Syria, Lucius Marcius Philippus. Philippus claimed descent from Alexander the Great, and was elected consul in 56 BC. Philippus never had much of an interest in young Octavius. Because of this, Octavius was raised by his grandmother (and Julius Caesar's sister), Julia Caesaris.

In 52 or 51 BC, Julia Caesaris died. Octavius delivered the funeral oration for his grandmother. From this point, his mother and stepfather took a more active role in raising him. He donned the toga virilis four years later, and was elected to the College of Pontiffs in 47 BC. The following year he was put in charge of the Greek games that were staged in honor of the Temple of Venus Genetrix, built by Julius Caesar. According to Nicolaus of Damascus, Octavius wished to join Caesar's staff for his campaign in Africa but gave way when his mother, Atia, protested. In 46 BC, she consented for him to join Caesar in Hispania, where he planned to fight the forces of Pompey, Caesar's late enemy, but Octavius fell ill and was unable to travel.

When he had recovered, he sailed to the front, but was shipwrecked; after coming ashore with a handful of companions, he crossed hostile territory to Caesar's camp, which impressed his great-uncle considerably. Velleius Paterculus reports that Caesar afterwards allowed the young man to share his carriage. When back in Rome, Caesar deposited a new will with the Vestal Virgins, naming Octavius as the prime beneficiary.

At the time Caesar was killed on the Ides of March (the 15th) 44 BC, Octavius was studying and undergoing military training in Apollonia, Illyria. Rejecting the advice of some army officers to take refuge with the troops in Macedonia, he sailed to Italia to ascertain if he had any potential political fortunes or security. After landing at Lupiae near Brundisium, he learned the contents of Caesar's will, and only then did he decide to become Caesar's political heir as well as heir to two-thirds of his estate. Having no living legitimate children, Caesar had adopted his great-nephew Octavius as his son and main heir. Upon his adoption, Octavius assumed his great-uncle's name, Gaius Julius Caesar. Although Romans who had been adopted into a new family usually retained their old nomen in cognomen form (e.g. Octavianus for one who had been an Octavius, Aemilianus for one who had been an Aemilius, etc.) there is no evidence that he ever bore the name Octavianus, as it would have made his modest origins too obvious. However, despite the fact that he never officially bore the name Octavianus, to save confusing the dead dictator with his heir, historians often refer to the new Caesar—between his adoption and his assumption, in 27 BC, of the name Augustus—as Octavian. Mark Antony later charged that Octavian had earned his adoption by Caesar through sexual favours, though Suetonius, in his work Lives of the Twelve Caesars, describes Antony's accusation as political slander.

To make a successful entry into the echelons of the Roman political hierarchy, Octavian could not rely on his limited funds. After a warm welcome by Caesar's soldiers at Brundisium, Octavian demanded a portion of the funds that were allotted by Caesar for the intended war against Parthia in the Middle East. This amounted to 700 million sesterces stored at Brundisium, the staging ground in Italy for military operations in the east. A later senatorial investigation into the disappearance of the public funds made no action against Octavian, since he subsequently used that money to raise troops against the Senate's arch enemy, Mark Antony. Octavian made another bold move in 44 BC when without official permission he appropriated the annual tribute that had been sent from Rome's Near Eastern province to Italy. Octavian began to bolster his personal forces with Caesar's veteran legionaries and with troops designated for the Parthian war, gathering support by emphasizing his status as heir to Caesar. On his march to Rome through Italy, Octavian's presence and newly-acquired funds attracted many, winning over Caesar's former veterans stationed in Campania. By June he had gathered an army of 3,000 loyal veterans, paying each a salary of 500 denarii.

Arriving in Rome on 6 May 44 BC, Octavian found the consul Mark Antony, Caesar's former colleague, in an uneasy truce with the dictator's assassins; they had been granted a general amnesty on 17 March, yet Antony succeeded in driving most of them out of Rome. This was due to his "inflammatory" eulogy given at Caesar's funeral, mounting public opinion against the assassins. Although Mark Antony was amassing political support, Octavian still had opportunity to rival him as the leading member of the faction supporting Caesar. Mark Antony had lost the support of many Romans and supporters of Caesar when he at first opposed the motion to elevate Caesar to divine status. Octavian failed to persuade Antony to relinquish Caesar's money to him. However, he managed to win support from Caesarian sympathizers during the summer, who saw the younger heir as the lesser evil in the hopes to manipulate him, or bear him while in their efforts to get rid of Antonius. In September, the Optimate orator Marcus Tullius Cicero began to attack Antony in a series of speeches, seeing Antony as the greatest threat to the order of the Senate. With opinion in Rome turning against him and his year of consular power nearing its end, Antony attempted to pass laws which would lend him control over Cisalpine Gaul, which had been assigned as part of his province, from Decimus Junius Brutus Albinus, one of Caesar's assassins. Octavian meanwhile built up a private army in Italy by recruiting Caesarian veterans, and on 28 November won over two of Antony's legions with the enticing offer of monetary gain. In the face of Octavian's large and capable force, Antony saw the danger of staying in Rome, and to the relief of the Senate he fled to Cisalpine Gaul, which was to be handed to him on 1 January.

After Actium and the defeat of Antony and Cleopatra, Octavian was in a position to rule the entire Republic under an unofficial principate. However, Octavian would have to achieve this through incremental gaining of power, courting the Senate and people, while upholding republican traditions of Rome to appear that he was not aiming for dictatorship or monarchy. Marching into Rome, Octavian and Marcus Agrippa were elected as dual consuls by the Senate. Years of civil war had left Rome in a state of near-lawlessness, but the Republic was not prepared to accept the control of Octavian as a despot. At the same time, Octavian could not simply give up his authority without risking further civil wars amongst the Roman generals, and even if he desired no position of authority whatsoever, his position demanded that he look to the well-being of the city of Rome and the Roman provinces. Octavian's aims from this point forward were to return Rome to a state of stability, traditional legality, and civility by lifting the overt political pressure imposed upon the courts of law and ensuring free elections, in name at least.

In 27 BC, Octavian formally returned full power to the Roman Senate and relinquished his control of the Roman provinces and their armies. However, under the consulship of Octavian, the Senate had little power in initiating legislation by introducing bills for senatorial debate. Although Octavian was no longer in direct control of the provinces and their armies, he retained the loyalty of active duty soldiers and veterans alike. The careers of many clients and adherents depended on his patronage, as his financial power in the Roman Republic was unrivaled.The historian Werner Eck states of Augustus:

The sum of his power derived first of all from various powers of office delegated to him by the Senate and people, secondly from his immense private fortune, and thirdly from numerous patron-client relationships he established with individuals and groups throughout the Empire. All of them taken together formed the basis of his auctoritas, which he himself emphasized as the foundation of his political actions.

To a large extent, the public was aware of the vast financial resources Augustus commanded. When Augustus failed to encourage enough senators to finance the building and maintenance of networks of roads in Italy, he took over direct responsibility of building roads in 20 BC. His construction of roads was publicized on the Roman currency issued in 16 BC, after he donated vast amounts of money to the aerarium Saturni, the public treasury.

According to H.H. Scullard, however, Augustus' power was based on the exercise of "...a predominant military power and that the ultimate sanction of his authority was force, however much the fact was disguised."

The Senate proposed to Octavian, the cherished victor of Rome's civil wars, to once again assume command of the provinces. The senate proposal was a ratification of Octavian's extra-constitutional power. Through the senate, Octavian was able to continue the appearance of a still-functional constitution of the Roman Republic. Whilst putting on the appearance of reluctance he accepted a ten year responsibility of overseeing provinces that were considered to be in a somewhat chaotic state. The provinces ceded to him to pacify within the promised ten year period comprised much of the conquered Roman world, including all of Hispania and Gaul, Syria, Cilicia, Cyprus, and Egypt. Moreover, command over these provinces provided Octavian with control over the majority of Rome's legions. While Octavian acted as consul in Rome, he dispatched senators to the provinces under his command as his representatives to manage provincial affairs and ensure his orders were carried out. On the other hand, the provinces not under Octavian's control were overseen by governors chosen by the Roman Senate.Octavian became the most powerful political figure in the city of Rome and in most of its provinces, yet he did not have a sole monopoly on political and martial power. The Senate still controlled North Africa, an important regional producer of grain, as well as Illyria and Macedonia, two martially strategic regions with several legions. However, with control of only five or six legions distributed amongst three senatorial proconsuls, compared to the 20 legions under the control of Augustus, the Senate's control of these regions did not amount to any political or martial challenge to Octavian. The Senate's control over some of the Roman provinces helped maintain a republican façade for the autocratic Principate, Octavian's control of entire provinces for the objective of securing peace and creating stability followed Republican-era precedents, in which prominent Romans such as Pompey had been granted similar military powers in times of crisis and instability.

In January of 27 BC, the Senate gave Octavian the new titles of Augustus and Princeps. Augustus, from the Latin word Augere (meaning to increase), can be translated as "the illustrious one". It was a title of religious rather than political authority. According to Roman religious beliefs, the title symbolized a stamp of authority over humanity—and in fact nature—that went beyond any constitutional definition of his status. After the harsh methods employed in consolidating his control, the change in name would also serve to demarcate his benign reign as Augustus from his reign of terror as Octavian. His new title of Augustus was also more favorable than Romulus, the previous one he styled for himself in reference to the story of Romulus and Remus (founders of Rome), which would symbolize a second founding of Rome. However, the title of Romulus was associated too strongly with notions of monarchy and kingship, an image Octavian tried to avoid. Princeps, comes from the Latin phrase primum caput, "the first head", originally meaning the oldest or most distinguished senator whose name would appear first on the senatorial roster; in the case of Augustus it became an almost regnal title for a leader who was first in charge. Princeps had also been a title under the Republic for those who had served the state well; for example, Pompey had held the title. Augustus also styled himself as Imperator Caesar divi filius, "Commander Caesar son of the deified one". With this title he not only boasted his familial link to deified Julius Caesar, but the use of Imperator signified a permanent link to the Roman tradition of victory. The word Caesar was merely a cognomen for one branch of the Julian family, yet Augustus transformed Caesar into a new family line that began with him.

Augustus was granted the right to hang the corona civica, the "civic crown" made from oak, above his door and have laurels drape his doorposts. This crown was usually held above the head of a Roman general during a triumph, with the individual holding the crown charged to continually repeat "memento mori", or, "Remember, you are mortal", to the triumphant general. Additionally, laurel wreaths were important in several state ceremonies, and crowns of laurel were rewarded to champions of athletic, racing, and dramatic contests. Thus, both the laurel and the oak were integral symbols of Roman religion and statecraft; placing them on Augustus' doorposts was tantamount to declaring his home the capital. However, Augustus renounced flaunting insignia of power such as holding a scepter, wearing a diadem, or wearing the golden crown and purple toga of his predecessor Julius Caesar. If he refused to symbolize his power by donning and bearing these items on his person, the Senate nonetheless awarded him with a golden shield displayed in the meeting hall of the Curia, bearing the inscription virtus, pietas, clementia, iustitia—"valor, piety, clemency, and justice."

In 23 BC, there was a political crisis that involved Augustus' co-consul Terentius Varro Murena, who was part of a conspiracy against Augustus. The exact details of the conspiracy are unknown, yet Murena did not serve a full term as consul before Calpurnius Piso was elected to replace him. Piso was a well known member of the republican faction, and serving as co-consul with him was another means by Augustus to show his willingness to make concessions and cooperate with all political parties. In the late spring Augustus suffered a severe illness, and on his supposed deathbed made arrangements that would put in doubt the senators' suspicions of his anti-republicanism. Augustus prepared to hand down his signet ring to his favored general Agrippa. However, Augustus handed over to his co-consul Piso all of his official documents, an account of public finances, and authority over listed troops in the provinces while Augustus' supposedly favored nephew Marcus Claudius Marcellus came away empty-handed. This was a surprise to many who believed Augustus would have named an heir to his position as an unofficial emperor. Augustus bestowed only properties and possessions to his designated heirs, as a system of institutionalized imperial inheritance would have provoked resistance and hostility amongst the republican-minded Romans fearful of monarchy.

Soon after his bout of illness subsided, Augustus gave up his permanent consulship. The only other times Augustus would serve as consul would be in the years 5 and 2 BC. Although he had resigned as consul, Augustus retained his consular imperium, leading to a second compromise between him and the Senate known as the Second Settlement. This was a clever ploy by Augustus; by stepping down as one of two consuls, this allowed aspiring senators a better chance to fill that position, while at the same time Augustus could "exercise wider patronage within the senatorial class." Augustus was no longer in an official position to rule the state, yet his dominant position over the Roman provinces remained unchanged as he became a proconsul.Earlier as a consul he had the power to intervene, when he deemed necessary, with the affairs of provincial proconsuls appointed by the Senate. As a proconsul Augustus did not want this authority of overriding provincial governors to be stripped from him, so imperium proconsulare maius, or "power over all the proconsuls" was granted to Augustus by the Senate.

Augustus was also granted the power of a tribune (tribunicia potestas) for life, though not the official title of tribune. Legally it was closed to patricians, a status that Augustus had acquired years ago when adopted by Julius Caesar. This allowed him to convene the Senate and people at will and lay business before it, veto the actions of either the Assembly or the Senate, preside over elections, and the right to speak first at any meeting. Also included in Augustus' tribunician authority were powers usually reserved for the Roman censor; these included the right to supervise public morals and scrutinize laws to ensure they were in the public interest, as well as the ability to hold a census and determine the membership of the Senate. With the powers of a censor, Augustus appealed to virtues of Roman patriotism by banning all other attire besides the classic toga while entering the Forum. There was no precedent within the Roman system for combining the powers of the tribune and the censor into a single position, nor was Augustus ever elected to the office of censor.Julius Caesar had been granted similar powers, wherein he was charged with supervising the morals of the state, however this position did not extend to the censor's ability to hold a census and determine the Senate's roster. The office of the tribune plebis began to lose its prestige due to Augustus' amassing of tribunal powers, so he revived its importance by making it a mandatory appointment for any plebeian desiring the praetorship.

In addition to tribunician authority, Augustus was granted sole imperium within the city of Rome itself: all armed forces in the city, formerly under the control of the prefects and consuls, were now under the sole authority of Augustus. With maius imperium proconsulare, Augustus was the only individual able to receive a triumph as he was ostensibly the head of every Roman army. In 19 BC, Lucius Cornelius Balbus, governor of Africa who defeated the Garamantes, was the first man of provincial origin to receive this award, as well as the last. For every following Roman victory the credit was given to Augustus, due to the fact that Rome's armies were commanded by the legatus, who were deputies of the princeps in the provinces. Augustus' eldest son by marriage to Livia, Tiberius, was the only exception to this rule when he received a triumph for victories in Germania in 7 BC. Ensuring that his status of maius imperium proconsulare was renewed in 13 BC, Augustus stayed in Rome during the renewal process and provided veterans with lavish donations to gain their support.

Many of the political subtleties of the Second Settlement seem to have evaded the comprehension of the Plebeian class. When Augustus failed to stand for election as consul in 22 BC, fears arose once again that Augustus was being forced from power by the aristocratic Senate. In 22, 21, and 19 BC, the people rioted in response, and only allowed a single consul to be elected for each of those years, ostensibly to leave the other position open for Augustus. In 22 BC there was a food shortage in Rome which sparked panic, while many urban plebs called for Augustus to take on dictatorial powers to personally oversee the crisis. After a theatrical display of refusal before the Senate, Augustus finally accepted authority over Rome's grain supply "by virtue of his proconsular imperium", and ended the crisis almost immediately. It was not until AD 8 that a food crisis of this sort prompted Augustus to establish a praefectus annonae, a permanent prefect who was in charge of procuring food supplies for Rome. In 19 BC, the Senate voted to allow Augustus to wear the consul's insignia in public and before the Senate, as well as sit in the symbolic chair between the two consuls and hold the fasces, an emblem of consular authority. Like his tribune authority, the granting of consular powers to him was another instance of holding power of offices he did not actually hold. This seems to have assuaged the populace; regardless of whether or not Augustus was actually a consul, the importance was that he appeared as one before the people. On 6 March 12 BC, after the death of Lepidus, he additionally took up the position of pontifex maximus, the high priest of the collegium of the Pontifices, the most important position in Roman religion. On 5 February 2 BC, Augustus was also given the title pater patriae, or "father of the country".

Later Roman Emperors would generally be limited to the powers and titles originally granted to Augustus, though often, to display humility, newly-appointed Emperors would often decline one or more of the honorifics given to Augustus. Just as often, as their reign progressed, Emperors would appropriate all of the titles, regardless of whether they had actually been granted them by the Senate. The civic crown, which later Emperors took to actually wearing, consular insignia, and later the purple robes of a Triumphant general (toga picta) became the imperial insignia well into the Byzantine era.

Imperator Caesar Divi Filius Augustus chose Imperator, "victorious commander" to be his first name, since he wanted to make the notion of victory associated with him emphatically clear. By the year 13, Augustus boasted 21 occasions where his troops proclaimed "imperator" as his title after a successful battle. Almost the entire fourth chapter in his publicly-released memoirs of achievements known as the Res Gestae was devoted to his military victories and honors. Pandering to Roman patriots, Augustus promoted the ideal of a superior Roman civilization with a task of ruling the world (the extent to which the Romans knew it), embodied in the phrase tu regere imperio populos, Romane, memento—"Roman, remember by your strength to rule the Earth's peoples!" This fit well with the Roman elite and the wider public opinion of the day which favored expansionism, reflected in a statement by the famous Roman poet Virgil who said that the gods had granted Rome imperium sine fine, "sovereignty without limit". There was public disappointment and regret for not avenging Crassus' captured battle standards when Augustus decided that the Middle Eastern power of Parthia should not be invaded. However, there were many other viable lands to be conquered.

By the end of his reign, the armies of Augustus had conquered northern Hispania (modern Spain and Portugal), the Alpine regions of Raetia and Noricum (modern Switzerland, Bavaria, Austria, Slovenia), Illyricum and Pannonia (modern Albania, Croatia, Hungary, Serbia, etc.), and extended the borders of the Africa Province to the east and south. After the reign of the client king Herod the Great (73–4 BC), Judea was added to the province of Syria when Augustus deposed his successor Herod Archelaus. Like Egypt which had been conquered after the defeat of Antony in 30 BC, Syria was governed not by a proconsul or legate of Augustus, but a high prefect of the equestrian class. Again, no military effort was needed in 25 BC when Galatia (modern Turkey) was converted to a Roman province shortly after Amyntas of Galatia was killed by an avenging widow of a slain prince from Homonada. When the rebellious tribes of Cantabria in modern-day Spain were finally quelled in 19 BC, the territory fell under the provinces of Hispania and Lusitania. This region proved to be a major asset in funding Augustus' future military campaigns, as it was rich in mineral deposits that could be fostered in Roman mining projects, especially the very rich gold deposits at Las Medulas for example.

Conquering the peoples of the Alps in 16 BC was another important victory for Rome since it provided a large territorial buffer between the Roman citizens of Italy and Rome's enemies in Germania to the north. The poet Horace dedicated an ode to the victory, while the monument Trophy of Augustus near Monaco was built to honor the occasion. The capture of the Alpine region also served the next offensive in 12 BC, when Tiberius began the offensive against the Pannonian tribes of Illyricum and his brother Nero Claudius Drusus against the Germanic tribes of the eastern Rhineland. Both campaigns were successful, as Drusus' forces reached the Elbe River by 9 BC, yet he died shortly after by falling off his horse. It was recorded that the pious Tiberius walked in front of his brother's body all the way back to Rome.

To protect the eastern areas of the Empire from the Parthian threat, Augustus relied on the client states of the east to act as territorial buffers and areas which could raise their own troops for defense. To ensure security of the Empire's eastern flank, Augustus stationed a Roman army in Syria just in case, while his skilled stepson Tiberius negotiated with the Parthians as Rome's diplomat to the East. One of Tiberius' greatest diplomatic achievements was negotiating for the return of Crassus' battle standards, a symbolic victory and great boost of morale for Rome. Tiberius was also responsible for restoring Tigranes V to the throne of Armenia.

Although Parthia always posed a threat to Rome in the east, the real battlefront was along the Rhine and Danube rivers. Before the final fight with Antony, Octavian's campaigns against the tribes in Dalmatia was the first step in expanding Roman dominions to the Danube. Victory in battle was not always a permanent success, as newly conquered territories were constantly retaken by Rome's enemies in Germania. A prime example of Roman loss in battle was the Battle of Teutoburg Forest in AD 9, where three entire legions led by Publius Quinctilius Varus were destroyed with few survivors by Arminius, leader of the Cherusci, an apparent Roman 'Ally'. Augustus retaliated by dispatching Tiberius and Drusus to the Rhineland to pacify it, which had some success although the battle of AD 9 brought the end to Roman expansion into Germany. The Roman general Germanicus took advantage of a Cherusci civil war between Arminius and Segestes; they defeated Arminius, who fled that battle but was killed later in 19 due to treachery.

The illness of Augustus in 23 BC brought the problem of succession to the forefront of political issues and the public. To ensure stability, he needed to designate an heir to his unique position in Roman society and government. This was to be achieved in small, undramatic, and incremental ways that did not stir senatorial fears of monarchy. If someone was to succeed his unofficial position of power, they were going to have to earn it through their own publicly-known merits. Some Augustan historians argue that indications pointed toward his sister's son Marcellus, who had been quickly married to Augustus' daughter Julia the Elder. Other historians dispute this due to Augustus' will read aloud to the Senate while he was seriously ill in 23 BC, instead indicating a preference for Marcus Agrippa, who was Augustus' second in charge and arguably the only one of his associates who could have controlled the legions and held the Empire together. After the death of Marcellus in 23 BC, Augustus married his daughter to Agrippa. This union produced five children, three sons and two daughters: Gaius Caesar, Lucius Caesar, Vipsania Julia, Agrippina the Elder, and Postumus Agrippa, so named because he was born after Marcus Agrippa died. Shortly after the Second Settlement, Agrippa was granted a five-year term of administering the eastern half of the Empire with the imperium of a proconsul and the same tribunicia potestas granted to Augustus (although not trumping Augustus' authority), his seat of governance stationed at Samos in the Cyclades. Although this granting of power would have shown Augustus' favor for Agrippa, it was also a measure to please members of his Caesarian party by allowing one of their members to share a considerable amount of power with him.

Augustus' intent to make Gaius and Lucius Caesar his heirs was apparent when he adopted them as his own children. He took the consulship in 5 and 2 BC so he could personally usher them into their political careers, and they were nominated for the consulships of AD 1 and 4. Augustus also showed favor to his stepsons, Livia's children from her first marriage, Nero Claudius Drusus Germanicus and Tiberius Claudius, granting them military commands and public office, and seeming to favor Drusus. However, Drusus' marriage to Antonia, Augustus' niece, was a relationship far too embedded within the family to disturb over succession issues. After Agrippa died in 12 BC, Livia's son Tiberius was ordered to divorce his own wife Vipsania and marry Agrippa's widow, Augustus' daughter Julia—as soon as a period of mourning for Agrippa had ended. While Drusus' marriage to Antonia was considered an unbreakable affair, Vipsania was "only" the daughter of the late Agrippa from his first marriage.

Tiberius shared in Augustus' tribune powers as of 6 BC, but shortly thereafter went into retirement, reportedly wanting no further role in politics while he exiled himself to Rhodes. Although no specific reason is known for his departure, it could have been a combination of reasons, including a failing marriage with Julia. It could very well have been from feelings of jealousy and being left out since Augustus' young grandchildren-turned-sons, Gaius and Lucius, joined the college of priests at an early age, were presented to spectators in a more favorable light, and were introduced to the army in Gaul. After the early deaths of both Lucius and Gaius in AD 2 and 4 respectively, and the earlier death of his brother Drusus (9 BC), Tiberius was recalled to Rome in June AD 4, where he was adopted by Augustus on the condition that he, in turn, adopt his nephew Germanicus. This continued the tradition of presenting at least two generations of heirs. In that year, Tiberius was also granted the powers of a tribune and proconsul, emissaries from foreign kings had to pay their respects to him, and by 13 was awarded with his second triumph and equal level of imperium with that of Augustus. The only other possible claimant as heir was Postumus Agrippa, who had been exiled by Augustus in AD 7, his banishment made permanent by senatorial decree, and Augustus officially disowned him. He certainly fell out of Augustus' favor as an heir; historian Erich S. Gruen notes various contemporary sources that state Postumus Agrippa was a "vulgar young man, brutal and brutish, and of depraved character."

On 19 August AD 14, Augustus died while visiting the place of his father's death at Nola, and Tiberius—who was present alongside Livia at Augustus' deathbed—was named his heir. Augustus' famous last words were, "Have I played the part well? Then applaud as I exit"—referring to the play-acting and regal authority that he had put on as emperor. Publicly, though, his last words were, "Behold, I found Rome of clay, and leave her to you of marble." An enormous funerary procession of mourners traveled with Augustus' body from Nola to Rome, and on the day of his burial all public and private businesses closed for the day. Tiberius and his son Drusus delivered the eulogy while standing atop two rostra. Coffin-bound, Augustus' body was cremated on a pyre close to his mausoleum. It was proclaimed that Augustus joined the company of the gods as a member of the Roman pantheon. In 410, during the Sack of Rome, the mausoleum was despoiled by the Goths and his ashes scattered.

Historian D.C.A. Shotter states that Augustus' policies of favoring the Julian family line over the Claudian should have been sufficient cause for Tiberius to show open disdain for Augustus after the latter's death; instead, Tiberius was always quick to rebuke those who criticized Augustus. Shotter suggests that Augustus' deification, coupled with Tiberius' "extremely conservative" attitude towards religion forced Tiberius to hold back any open resentment he might have harbored. Also, historian R. Shaw-Smith points to letters of Augustus to Tiberius which display affection towards Tiberius and high regard for his military merits. Shotter states that Tiberius focused his anger and criticism on Gaius Asinius Gallus (for marrying Vipsania after Augustus forced Tiberius to divorce her) as well as the two young Caesars Gaius and Lucius, instead of Augustus, the real architect of his divorce and imperial demotion.

Augustus' reign laid the foundations of a regime that lasted hundreds of years until the ultimate decline of the Roman Empire. Both his borrowed surname, Caesar, and his title Augustus became the permanent titles of the rulers of Roman Empire for fourteen centuries after his death, in use both at Old Rome and New Rome. In many languages, caesar became the word for emperor, as in the German Kaiser and in the Bulgarian and subsequently Russian Tsar. The cult of Divus Augustus continued until the state religion of the Empire was changed to Christianity in 391 by Theodosius I. Consequently, there are many excellent statues and busts of the first emperor. He had composed an account of his achievements, the Res Gestae Divi Augusti, to be inscribed in bronze in front of his mausoleum. Copies of the text were inscribed throughout the Empire upon his death. The inscriptions in Latin featured translations in Greek beside it, and were inscribed on many public edifices, such as the temple in Ankara dubbed the Monumentum Ancyranum, called the "queen of inscriptions" by historian Theodor Mommsen. There are a few known written works by Augustus that have survived. This includes his poems Sicily, Epiphanus, and Ajax, an autobiography of 13 books, a philosophical treatise, and his written rebuttal to Brutus' Eulogy of Cato. However, historians are able to analyze existing letters penned by Augustus to others for additional facts or clues about his personal life.

Many consider Augustus to be Rome's greatest emperor; his policies certainly extended the Empire's life span and initiated the celebrated Pax Romana or Pax Augusta. He was intelligent, decisive, and a shrewd politician, but he was not perhaps as charismatic as Julius Caesar, and was influenced on occasion by his third wife, Livia (sometimes for the worse). Nevertheless, his legacy proved more enduring. The city of Rome was utterly transformed under Augustus, with Rome's first institutionalized police force, fire fighting force, and the establishment of the municipal prefect as a permanent office. The police force was divided into cohorts of 500 men each, while the units of firemen ranged from 500 to 1,000 men each, with 7 units assigned to 14 divided city sectors. A praefectus vigilum, or "Prefect of the Watch" was put in charge of the vigiles, Rome's fire brigade and police. With Rome's civil wars at an end, Augustus was also able to create a standing army for the Roman Empire, fixed at a size of 28 legions of about 170,000 soldiers. This was supported by numerous auxiliary units of 500 soldiers each, often recruited from recently conquered areas. With his finances securing the maintenance of roads throughout Italy, Augustus also installed an official courier system of relay stations overseen by a military officer known as the praefectus vehiculorum. Besides the advent of swifter communication amongst Italian polities, his extensive building of roads throughout Italy also allowed Rome's armies to march swiftly and at an unprecedented pace across the country. In the year 6 Augustus established the aerarium militare, donating 170 million sesterces to the new military treasury that provided for both active and retired soldiers. One of the most lasting institutions of Augustus was the establishment of the Praetorian Guard in 27 BC, originally a personal bodyguard unit on the battlefield that evolved into an imperial guard as well as an important political force in Rome. They had the power to intimidate the Senate, install new emperors, and depose ones they disliked; the last emperor they served was Maxentius, as it was Constantine I who disbanded them in the early 4th century and destroyed their barracks, the Castra Praetoria.

Although the most powerful individual in the Roman Empire, Augustus wished to embody the spirit of Republican virtue and norms. He also wanted to relate to and connect with the concerns of the plebs and lay people. He achieved this through various means of generosity and a cutting back of lavish excess. In the year 29 BC, Augustus paid 400 sesterces each to 250,000 citizens, 1,000 sesterces each to 120,000 veterans in the colonies, and spent 700 million sesterces in purchasing land for his soldiers to settle upon. He also restored 82 different temples to display his care for the Roman pantheon of deities. In 28 BC, he melted down 80 silver statues erected in his likeness and in honor of him, an attempt of his to appear frugal and modest.

The longevity of Augustus' reign and its legacy to the Roman world should not be overlooked as a key factor in its success. As Tacitus wrote, the younger generations alive in AD 14 had never known any form of government other than the Principate. Had Augustus died earlier (in 23 BC, for instance), matters might have turned out differently. The attrition of the civil wars on the old Republican oligarchy and the longevity of Augustus, therefore, must be seen as major contributing factors in the transformation of the Roman state into a de facto monarchy in these years. Augustus' own experience, his patience, his tact, and his political acumen also played their parts. He directed the future of the Empire down many lasting paths, from the existence of a standing professional army stationed at or near the frontiers, to the dynastic principle so often employed in the imperial succession, to the embellishment of the capital at the emperor's expense. Augustus' ultimate legacy was the peace and prosperity the Empire enjoyed for the next two centuries under the system he initiated. His memory was enshrined in the political ethos of the Imperial age as a paradigm of the good emperor. Every emperor of Rome adopted his name, Caesar Augustus, which gradually lost its character as a name and eventually became a title. The Augustan era poets Virgil and Horace praised Augustus as a defender of Rome, an upholder of moral justice, and an individual who bore the brunt of responsibility in maintaining the empire. However, for his rule of Rome and establishing the principate, Augustus has also been subjected to criticism throughout the ages. The contemporary Roman jurist Marcus Antistius Labeo (d. 10 or 11 AD), fond of the days of pre-Augustan republican liberty in which he had been born, openly criticized the Augustan regime. In the beginning of his Annals, the Roman historian Tacitus (c. 56–c.117) wrote that Augustus had cunningly subverted Republican Rome into a position of slavery. He continued to say that, with Augustus' death and swearing of loyalty to Tiberius, the people of Rome simply traded one slaveholder for another. Tacitus, however, records two contradictory but common views of Augustus:

Intelligent people praised or criticized him in varying ways. One opinion was as follows. Filial duty and a national emergency, in which there was no place for law-abiding conduct, had driven him to civil war--and this can neither be initiated nor maintained by decent methods. He had made many concessions to Anthony and to Lepidus for the sake of vengeance on his father's murderers. When Lepidus grew old and lazy, and Anthony's self-indulgence got the better of him, the only possible cure for the distracted country had been government by one man. However, Augustus had put the state in order not by making himself king or dictator, but by creating the Principate. The empire's frontiers were on the ocean, or distant rivers. Armies, provinces, fleets, the whole system was interrelated. Roman citizens were protected by the law. Provincials were decently treated. Rome itself had been lavishly beautified. Force had been sparingly used--merely to preserve peace for the majority.

According to the second opposing opinion:

filial duty and national crisis had been merely pretexts. In actual fact, the motive of Octavian, the future Augustus, was lust for power...There had certainly been peace, but it was a blood-stained peace of disasters and assassinations.

In a recent biography on Augustus, Anthony Everitt asserts that through the centuries, judgments on Augustus' reign have oscillated between these two extremes but stresses that:

"Opposites do not have to be mutually exclusive, and we are not obliged to choose one or the other. The story of his career shows that Augustus was indeed ruthless, cruel, and ambitious for himself. This was only in part a personal trait, for upper-class Romans were educated to compete with one another and to excel. However, he combined an overriding concern for his personal interests with a deep-seated patriotism, based on a nostalgia of Rome's antique virtues. In his capacity as princeps, selfishness and selflessness coexisted in his mind. While fighting for dominance, he paid little attention to legality or to the normal civilities of political life. He was devious, untrustworthy, and bloodthirsty. But once he had established his authority, he governed efficiently and justly, generally allowed freedom of speech, and promoted the rule of law. He was immensely hardworking and tried as hard as any democratic parliamentarian to treat his senatorial colleagues with respect and sensitivity. He suffered from no delusions of grandeur."

Tacitus was of the belief that Nerva (r. 96–98) successfully "mingled two formerly alien ideas, principate and liberty." The 3rd century historian Cassius Dio acknowledged Augustus as a benign, moderate ruler, yet like most other historians after the death of Augustus, Dio viewed Augustus as an autocrat. The poet Marcus Annaeus Lucanus (39–65 AD) was of the opinion that Caesar's victory over Pompey and the fall of Cato the Younger (95 BC–46 BC) marked the end of traditional liberty in Rome; historian Chester G. Starr, Jr. writes of his avoidance of criticizing Augustus, "perhaps Augustus was too sacred a figure to accuse directly."

The Anglo-Irish writer Jonathan Swift (1667–1745), in his Discourse on the Contests and Dissentions in Athens and Rome, criticized Augustus for installing tyranny over Rome, and likened what he believed Great Britain's virtuous constitutional monarchy to Rome's moral Republic of the 2nd century BC. In his criticism of Augustus, the admiral and historian Thomas Gordon (1658–1741) compared Augustus to the puritanical tyrant Oliver Cromwell (1599–1658). Thomas Gordon and the French political philosopher Montesquieu (1689–1755) both remarked that Augustus was a coward in battle. In his Memoirs of the Court of Augustus, the Scottish scholar Thomas Blackwell (1701–1757) deemed Augustus a Machiavellian ruler, "a bloodthirsty vindicative usurper", "wicked and worthless", "a mean spirit", and a "tyrant".

Augustus' public revenue reforms had a great impact on the subsequent success of the Empire. Augustus brought a far greater portion of the Empire's expanded land base under consistent, direct taxation from Rome, instead of exacting varying, intermittent, and somewhat arbitrary tributes from each local province as Augustus' predecessors had done. This reform greatly increased Rome's net revenue from its territorial acquisitions, stabilized its flow, and regularized the financial relationship between Rome and the provinces, rather than provoking fresh resentments with each new arbitrary exaction of tribute. The measures of taxation in the reign of Augustus were determined by population census, with fixed quotas for each province. Citizens of Rome and Italy paid indirect taxes, while direct taxes were exacted from the provinces. Indirect taxes included a 4% tax on the price of slaves, a 1% tax on goods sold at auction, and a 5% tax on the inheritance of estates valued at over 100,000 sesterces by persons other than the next of kin.

An equally important reform was the abolition of private tax farming, which was replaced by salaried civil service tax collectors. Private contractors that raised taxes had been the norm in the Republican era, and some had grown powerful enough to influence the amount of votes for politicians in Rome. The tax farmers had gained great infamy for their depredations, as well as great private wealth, by winning the right to tax local areas. Rome's revenue was the amount of the successful bids, and the tax farmers' profits consisted of any additional amounts they could forcibly wring from the populace with Rome's blessing. Lack of effective supervision, combined with tax farmers' desire to maximize their profits, had produced a system of arbitrary exactions that was often barbarously cruel to taxpayers, widely (and accurately) perceived as unfair, and very harmful to investment and the economy.

The use of Egypt's immense land rents to finance the Empire's operations resulted from Augustus' conquest of Egypt and the shift to a Roman form of government. As it was effectively considered Augustus' private property rather than a province of the Empire, it became part of each succeeding emperor's patrimonium. Instead of a legate or proconsul, Augustus installed a prefect from the equestrian class to administer Egypt and maintain its lucrative seaports; this position became the highest political achievement for any equestrian besides becoming Prefect of the Praetorian Guard. The highly productive agricultural land of Egypt yielded enormous revenues that were available to Augustus and his successors to pay for public works and military expeditions, as well as bread and circuses for the population of Rome.

The month of August (Latin: Augustus) is named after Augustus; until his time it was called Sextilis (named so because it had been the sixth month of the original Roman calendar and the Latin word for six was sex). Commonly-repeated lore has it that August has 31 days because Augustus wanted his month to match the length of Julius Caesar's July, but this is an invention of the 13th century scholar Johannes de Sacrobosco. Sextilis in fact had 31 days before it was renamed, and it was not chosen for its length (see Julian calendar). According to a senatus consultum quoted by Macrobius, Sextilis was renamed to honor Augustus because several of the most significant events in his rise to power, culminating in the fall of Alexandria, fell in that month.(Note that it was not his birthday month.)

On his deathbed, Augustus boasted "I found Rome of bricks; I leave it to you of marble". Although there is some truth in the literal meaning of this, Cassius Dio asserts that it was a metaphor for the Empire's strength. Marble could be found in buildings of Rome before Augustus, but it was not extensively used as a building material until the reign of Augustus. Although this did not apply to the Subura slums, which were still as rickety and fire-prone as ever, he did leave a mark on the monumental topography of the centre and of the Campus Martius, with the Ara Pacis (Altar of Peace) and monumental sundial, whose central gnomon was an obelisk taken from Egypt. The relief sculptures decorating the Ara Pacis visually augmented the written record of Augustus' triumphs in the Res Gestae. Its reliefs depicted the imperial pageants of the praetorians, the Vestals, and the citizenry of Rome. He also built the Temple of Caesar, the Baths of Agrippa, and the Forum of Augustus with its Temple of Mars Ultor. Other projects were either encouraged by him, such as the Theatre of Balbus, and Agrippa's construction of the Pantheon, or funded by him in the name of others, often relations (eg Portico of Octavia, Theatre of Marcellus). Even his Mausoleum of Augustus was built before his death to house members of his family. To celebrate his victory at the Battle of Actium, the Arch of Augustus was built in 29 BC near the entrance of the Temple of Castor and Pollux, and widened in 19 BC to include a triple-arch design. There are also many buildings outside of the city of Rome that bear Augustus' name and legacy, such as the Theatre of Merida in modern Spain, the Maison Carrée built at Nîmes in today's southern France, as well as the Trophy of Augustus at La Turbie, located near Monaco.

After the death of Agrippa in 12 BC, a solution had to be found in maintaining Rome's water supply system. This came about because it was overseen by Agrippa when he served as aedile, and was even funded by him afterwards when he was a private citizen paying at his own expense. In that year, Augustus arranged a system where the Senate designated three of its members as prime commissioners in charge of the water supply and to ensure that Rome's aqueducts did not fall into disrepair. In the late Augustan era, the commission of five senators called the curatores locorum publicorum iudicandorum (translated as "Supervisors of Public Property") was put in charge of maintaining public buildings and temples of the state cult. Augustus created the senatorial group of the curatores viarum (translated as "Supervisors for Roads") for the upkeep of roads; this senatorial commission worked with local officials and contractors to organize regular repairs.

The Corinthian order of architectural style originating from ancient Greece was the dominant architectural style in the age of Augustus and the imperial phase of Rome. Suetonius once commented that Rome was unworthy of its status as an imperial capital, yet Augustus and Agrippa set out to dismantle this sentiment by transforming the appearance of Rome upon the classical Greek model.