This article seeks to highlight some of the most notable Roman emperors and their significant impact on Rome’s historical trajectory. From the inauguration of Augustus in 27 BC until the fall of Romulus Augustus in 476 AD, Rome was under the rule of numerous emperors, each contributing to the shaping and reshaping of one of history’s most formidable empires.

The Romans Emperors played a significant role in shaping the Roman Empire and its historical significance. From initiating monumental architectural projects to ushering in religious and political reforms, these emperors left an indelible mark on world history. However, it’s important to note that their reigns were also marked by endless warfare, power struggles, and societal upheavals.

The study of Roman emperors serves as an essential lens into understanding the complexities and dynamics of power and rule. It provides a profound insight into the successes and failures of one of the most formidable and influential civilizations in human history.

Augustus (27 BC – 14 AD): The First Roman Emperor

Augustus, originally known as Octavian, was the grand-nephew of Julius Caesar. After Caesar’s assassination, Augustus effectively ended a century of civil wars and laid the foundation for a period of peace and prosperity known as Pax Romana – or Pax Augusta after him. He introduced a political system where he preserved the form of the Roman Republic but held the majority of the political power. The Principate system of government established by Augustus lasted until the Crisis of the Third Century.

Augustus reformed the Roman tax system, established a standing army and created the Praetorian Guard. It was also during his reign that a network of roads with an official courier service was created. Within Rome, he launched important large-scale rebuilding projects and created both an official police force and a fire-fighting service.

During the reign of Augustus, the Roman Empire was largely free of major armed conflicts, expect for certain expansionary wars. (After his death, a period of social and political instability followed, including the Year of the Four Emperors.) Augustus protected the empire’s frontier regions by accumulating strategically located client states, and he also ended hostilites with the Parhian Empire through diplomatic means.

The Roman Empire expanded drastically during the reign of Augustus, as he annexed Egypt, Dalmatia, Pannonia, Noricum, and Raetia, completed the Roman conquest of the Iberian penninsula, and spread Roman control to several parts of Africa. He was not as successful in northern Europe, where Roman forces suffered major setbacks in Germania.

Emperor Augustus died at age 75 in AD 14. Persistent rumors claimed that his wife Livia had poisoned him, but no significant evidence for this has been found. Augustus adopted son Tiberius – who was Livia’s son from a previous relationship and also the previous husband of Augustus only biological child Julia – succeeded Augustus as Emperor of Rome.

Background and rise to power

Octavian was born into an equestrian branch of the plebeian gens Octavia, and was the maternal grand-nephew of Julius Caesar. Caesar named him as his adopted son and heir in his will, and after the assassination of Caesar, Octavian received not just his material possessions but also the loaylty of his legions.

Octavian, Mark Antony, and Marcus Lepidus formed the Second Triumvirate and defeated the group who had orchestrated the assassination of Caesar. After the Battle of Philippi in 42 BC, the three ruled the empire as de facto dictators.

Eventually, the years of cooperation between the three men came to an end. Lepidus was exiled in 36 BC and Antony was defeated by Octavian in 31 BC. As Octavian forces invaded Egypt, Antony and his wife Queen Cleopatra of Egypt killed themselves, and Egypt became a Roman province.

Octavian (Augustus) restored the facade of the Roman Republic and its institutions, but in reality ruled the empire as an autocrat as he had the Senate grant him lifetime tenure as commander-in-chief, tribune and censor.

Trajan (98 AD – 117 AD): The Optimus Princeps

Regarded as the embodiment of the perfect Roman emperor, Trajan was known for his military expansion and public building programs. He is famed for his successful military campaigns, primarily against Dacia (modern-day Romania), leading to territorial expansion, increased resources and wealth for the Roman Empire. By the time of his death, the Roman Empire had reached its greatest territorial extent.

Famous for his political skills and philantropic projects, Trajan is considered one of the so-called Five Good Emperors of Nerva-Antonine dynasty. During his reign, he spearheaded several notable building projects in Rome, including the forum named after him, and also established important social welfare programs, such as the alimenta.

Popular with the Roman army, Trajan managed to annex Nabataea, and incorporate Armenia, Mesopotamia, and Assyria as Roman provinces through successful wars against the Parthians.

Trajan died of a stroke in the city of Selinus in AD 117, after falling ill on a ship heading back to Rome. His ashes were entombed beneath Trajan’s Column. Trajan was succeeded by his cousin Emperor Hadrian.

Background and rise to power

Trajan was born in the municipium of Italica, in what is today the province of Seville in Andalusia, Spain. Back then, this was the location of an Italic settlement. Trajan’s gens Ulpia came from the town Tuder in the Umbria region of central Italy. Trajan was born into a well-known family, as his father Marcus Ulpius Traianus was a general and distinguished senator.

Trajan began accumulating power durng the reign of Domitian. In AD 89, when he was serving as legatus legionis in Hispania Tarraconensis, he supported Emperor Domitian against a revolt led by Antonius Saturninus. He was later appointed governor of Germania and Pannonia.

Through successful campaigning against Germanic tribes, Trajan earned a good reputation among the Roman soldiers. In September AD 96, Emperor Domitian was succeeded by Emperor Nerva, who was old, childless and not popular with the army. Members of the Praetorian Guard revolted, and Nerva decided to adopt the popular Trajan as his heir and successor.

Hadrian (117 AD – 138 AD): The Architect Emperor

Hadrian, Trajan’s successor, is remembered for his significant architectural contributions, including the construction of the Pantheon and the infamous Hadrian’s Wall in Britain. His reign was marked by consolidation of the empire, including the withdrawal of troops from Eastern provinces and focusing on culturally unifying the empire.

Soon after becoming emperor, Hadrian ordered the unlawful killing of four leading senators, and this resulted in a lifelong enmity between him and the senate. He also further angered the senate by abandoning Trajan’s expansionist policies for the Middle East and Dacia.

Instead of focusing on expansion, Hadrian invested in defensible borders and aimed to unify the peoples within the empire. He visited almost every province and was not foreign to intervene directly in provincial affairs, especially when it concerned building projects. This included Hadrian’s Wall, which marked the northern border of the Roman empire on the British Isles. Hadrian also oversaw several notable building projects in Rome itself, such as the Temple of Venus and Roma, and he ordered the rebuilding of the Pantheon.

In AD 138, the childless Hadrian adopted Antonius Pius and nominated him as his successor, on condition that Pius adopted Marcus Aurelius and Lucius Verus as his heirs. Hadrian died that same year in Baiae, after several years of health problems.

Background and rise to power

Hadrian was born in Italica on the Iberian Penninsula in AD 76. His branch of the Aelia gens, the Aeli Hadriani, originated from the town Hadria in eastern Italy.

Hadrian is a member of the Nerva-Antonine dynasty.

Early in his political career, Hadrian married Vibia Sabina. She was the grandniece of Trajan, and Hadrian married her several years before Trajan became emperor. Both the marriage and Hadrian’s later succession as emperor are believed to have been strongly promoted by Trajan´s wife Pompeia Plotina.

Marcus Aurelius (161 AD – 180 AD): The Philosopher King

Apart from being an efficient emperor, Marcus Aurelius was also known as a philosopher king for his adoption and promotion of Stoicism. He was the last of the so-called Five Good Emperors and the final emperor of the Pax Romana.

His reign was marked by continuous warfare at the empire’s northern borders, and he authored ‘Meditations’, an introspective series of personal reflections that made him a significant figure in Stoic philosophy. His writings remain a significant source for our modern understanding of ancient Stoic philosophy, and Meditations are still read, loved and dicussed today.

Under the reign of Marcus Aurelius, the Roman Empire was marred by significant military conflicts. In the East, they battled a revitalized Parthian Empire and struggled with rebels in the Kingdom of Armenia. In the north, the Marcomannic Wars lasted from about 166 to 180 AD, where the Roman Army fought against the Germanic Marcomanni and Quadi, the Sarmatian lazyges, and several other Germanic, Sarmatian and Gothic peoples along the river Danube, which as the Empire´s northeastern border.

Although largely successful in these conflicts, they strained the Roman economy and Emperor Marcus Aurelius reduced the silver purity of the denarius (the Roman currency).

In 165-166, a devastating plague broke out in the Roman Empire and caused the death of an estimated 5-10 million people. It is possible that it came to Rome with soldiers returning from war in the Near East. The plague is generally believed to have been smallpox, but some sources suggest measles as a more likely culprit. Marcus Aurelius co-regnant Lucius Verus died in AD 169, probably a victim of the plague.

During the last few years of this life, from AD 177 to 180, Marcus Aurelius co-ruled Rome with his son Commodus. After Marcus Aurelius death in AD 180, Commodus became the sole emperor.

Background and rise to power

Marcus Aurelius Antoninus, the son of the praetor Marcus Annius Verus and his wife Domitia Calvilla, was born in Rome on 26 April AD 121.

Marcus Aurelius´s father died when his son was just three years old, and the future emperor was raised by his mother and paternal grandfather. Domitia Calvilla was the daughter of a Roman patrician and inherited a great fortune from her parents and grandparents, including large brickworks on the outskirts of Rome and a villa on the Caelian hill. Marcus Aurelius was born and raised in the Horti and referred to the Caelian hill as “My Caelian”.

In AD 138, when Marcus Antonius was still young, the childless Emperor Hadrian adopted Antonius Pius and nominated him as his successor, on condition that Antonius adopted Marcus Aurelius and Lucius Verus as his heirs. Therefore, Marcus Antonius was adopted at the age of 17.

Being in line to the throne, Marcus Aurelius wad educated by tutors such as Herodes Atticus and Marcus Cornelius Fronto, learning both Greek and Latin. He served as Roman consul in AD 140, 145, and 161, and married Antonio’s daughter Faustina in AD 145.

Marcus Aurelius acceded to the throne alonside his adoptive brother Lucius Verus after Antonius Pius’s death in AD 161. He was a member of the Nerva-Antonine dynasty, and his adopted family was the gens Aurelia.

Constantine the Great (306 AD – 337 AD): The Christian Emperor

Constantine the Great is known for religious and administrative reforms that significantly shaped the future of the empire. Notably, he convened the Council of Nicaea, leading to the creation of the Nicene Creed, a significant thread in Christian orthodoxy. Constantine also shifted the empire’s capital to Byzantium, renaming it Constantinople.

Constantine was the first Roman emperor to become a Christian, and the period when Christianity was decriminalized in Rome and the persecution of Christians within the empire came to a halt is known as the Constantinian shift. Constantine adhered to a religiopolitical ideology which emphazised the unity of church and state, and opposed to any separation of the two.

After becoming emperor in AD 324, Constantine carried out several reforms to strengthen the empire, including a restruction of the government that separated the civil authory from the military one. He also reorganised the Roman army to form mobile units called comitatenses and frontier-garrison troops called limitanei.

Inflation had become a problem within the empire, and Emperor Constantine introduced a new gold coin named the solidus. This coin would remain the standard currency for Byzantine for more than a millenium.

During his reign, Constantine had to manage numerous campaigns against hostile tribes along the Roman frontiers, such as the Sarmatians, the Goths, the Alemannia, and the Franks. He also successfully resettled (re-Romanized) certain territories that had been abandonned by the empire during the Crisis of the Third Century.

The age of Constantine is regarded as pivotal in the transition from classical antiquity to the Middle Ages. He established a new imperial residence in Byzantum and declared it New Rome, before naming it Constantinople after himself. Even long after his reign, when the Western Roman Empire finaly collapsed in the 5th centuryd AD, the Easter Roman Empire – based in Constantinople and today known as the Byzantine Empire – continued until the fall of Constantinople to the Ottoman Empire in AD 1453.

Emperor Constantine left the Roman Empire to his sons, thus continuing the Constantinian dynasty.

Background and rise to power

Constantine was born in Naissus in Dacia Mediterranea circa AD 272. This location is today a part of Serbia. His father was the Roman army officer Flavius Constantius, who reigned as Emperor Constantinus I in 305-306, and this mother Helena was a Greek woman of low birth, probably from Asia Minor. The Christian church would later credit her for her son´s conversion to Christianity and canonise her as Saint Helena.

Constantine’s orignal full name remains unknown and his praenomen is variously given as Lucius, Marcus, and Gaius.

Constantine served with distinction under Emperor Diocletian and Emperor Galerius. His military career started in the eastern provinces where he campaigned against the Persians, before being sent to the province of Britannia in AD 305 to fight alongside his father. After his father´s death the following year, Constantine was acclaimed augustus (emperor) by his army at Eboracum (now York, England).

In AD 324, Constantine became the sole ruler of the Roman Empire efter winning the civil wars against the emperors Maxentius and Licinius.