Caligula, Nero, Domitian, Commodus, Elagabalus, Caracalla and Tiberius are often named among the worst Roman emperors. Between AD 14 and 222, these seven rulers earned reputations for cruelty, extravagance or the abuse of imperial power, although their records differed considerably. Some had relatives and rivals killed, while others faced military rebellions, alienated the Senate or were overthrown by conspirators inside the palace. Their administrations also achieved things that hostile accounts rarely allow to dominate the story.
There is no objective measure by which historians can rank the worst Roman emperors. The fullest surviving accounts often come from senators and aristocratic biographers, sometimes writing after an emperor’s assassination and official disgrace. They describe genuine acts of violence alongside familiar charges of madness, sexual scandal and reckless expenditure. An emperor hated by senators could still command loyalty among his soldiers or approval from people in Rome and the provinces. Those different experiences have to be considered together.
The empire survived the assassinations, civil wars and succession disputes surrounding these seven men. Their decisions and their consequences must be weighed alongside the circumstances in which later Romans wrote about them.
1. Caligula (AD 37–41)
Gaius Caesar became emperor in AD 37. The nickname Caligula, meaning ‘little boot,’ came from his childhood among the Roman armies on the Rhine with his father, the celebrated commander Germanicus. His mother, Agrippina the Elder, and two older brothers had suffered under Tiberius, so the new reign raised hopes that the fear surrounding the imperial household would end. Gaius recalled exiles and arranged public celebrations, and his first months brought widespread goodwill.
Relations with the Senate soon deteriorated. Ancient writers recount accusations of conspiracy, the confiscation of property, executions and the deliberate humiliation of senators. Suetonius’s biography, composed decades after Gaius’s death, includes the notorious story that he considered appointing his horse consul. The horse story is difficult to verify. If Gaius threatened to elevate a horse, it may have been a calculated insult to senators whose high offices ultimately depended on the emperor’s favour.
Gaius suffered an illness during his first year as emperor. Claims that the illness permanently damaged his mind rest on much weaker evidence. Aloys Winterling’s reassessment of Caligula approaches his escalating behaviour through the breakdown of relations between the emperor and the Roman aristocracy, providing a political explanation for actions that hostile authors present as senseless. The evidence of intimidation and executions remains serious, whatever judgment is made about his mental health.
Gaius’s conflict with Jewish communities centred on the Temple at Jerusalem. In AD 40, Gaius ordered a statue of himself to be installed there, in defiance of local religious prohibitions on such images. Philo of Alexandria witnessed the wider dispute and described the emperor’s demands in his Embassy to Gaius. Jewish communities resisted, while the Syrian governor Publius Petronius delayed carrying out the order. Violence appeared increasingly possible, but the statue was never installed. Gaius died before the confrontation reached its threatened outcome.
On 24 January AD 41, Gaius was murdered in Rome by officers of the Praetorian Guard, among them Cassius Chaerea. The conspirators also killed his wife Caesonia and their young daughter. Senators briefly considered reviving republican government, only for the guards to proclaim Gaius’s uncle Claudius emperor. The guards’ choice of Claudius left the Senate little authority over the succession. Gaius had also shown what could happen when an emperor lost the protection of his own guards.
2. Nero (AD 54–68)
Nero inherited the throne from Claudius in AD 54, aged seventeen. His mother Agrippina the Younger had arranged his adoption into the ruling family; during his early years, the philosopher Seneca and the praetorian prefect Burrus were influential advisers. The new government maintained the administration of the provinces and initially worked with the Senate. Nero’s fourteen-year reign began with relatively cooperative government, although later accounts emphasised scandal and violence.
The struggle for influence within Nero’s family soon led to killings. His stepbrother Britannicus died in AD 55, and ancient writers alleged poisoning. In AD 59, after an attempt to kill Agrippina the Younger in a staged accident at sea failed, Nero had his mother murdered. His former wife Octavia was exiled and executed in AD 62. These killings removed figures whose position or connections could threaten his rule and personal arrangements. Suetonius tells many sensational stories about Nero, but the dynastic murders have a firmer place in the surviving historical tradition than many allegations about his private life.
The fire that devastated much of Rome in July AD 64 added a new charge to Nero’s reputation. Tacitus’s account of the fire reports that the emperor was at Antium when it started and returned to provide relief and temporary housing. Rumours nevertheless held him responsible for setting the city alight, although no surviving evidence proves he ordered the fire. The familiar image of Nero playing a violin while Rome burned is anachronistic, since the instrument did not yet exist. Construction of his extravagant Golden House on land made available by the destruction helped sustain the rumours.
Tacitus also reports that Nero punished Christians in response to accusations surrounding the blaze. In Annals 15.44, he describes executions involving dogs, crucifixion and burning. The exact scale and details of the killings cannot be independently established. His passage concerns the persecution following the fire in Rome; it does not document a continuous empire-wide policy against Christians.
Nero also performed music, sang and competed in chariot races in public. Some spectators enjoyed his performances; elite authors objected to the spectacle of an emperor competing in occupations associated with professional entertainers. In AD 68, Vindex rebelled in Gaul, and Galba in Spain emerged as a rival for imperial power. Nero lost support within the military and his own entourage and killed himself. The Julio-Claudian dynasty ended with him, followed by the civil wars of AD 68–69 and four competing emperors. With the dynasty ended, rival commanders settled the succession by force.
3. Domitian (AD 81–96)
Domitian took power in AD 81 after the death of his brother Titus. He was the younger son of Vespasian, whose dynasty had brought order after the civil war of AD 69. Domitian directed extensive building projects in Rome, kept close control over imperial officials and strengthened parts of the frontier administration. His palace on the Palatine and other public buildings attest to the scale of construction undertaken during his rule.
Senators resented Domitian’s increasingly coercive treatment of their order. Suetonius recounts treason proceedings, property seizures and executions, especially in the final years. After Saturninus, the governor on the Rhine, rebelled in AD 89, suspicions of conspiracy grew more intense. Domitian asserted control and demanded forms of court deference that senators regarded as degrading, particularly because the old institutions still carried the language and prestige of republican consultation.
The claim that Domitian insisted on being called ‘lord and god’ is often overstated. According to Suetonius, officials used the phrase dominus et deus in an imperial letter and the wording subsequently spread. It helps explain the senatorial hostility toward his court, but does not establish that a law compelled everyone in the empire to address him that way.
Domitian’s record on the frontiers was mixed. On the Rhine he fought the Chatti; across the Danube, conflict involved Dacians and Sarmatian peoples. Suetonius acknowledges reverses alongside victories. The agreement Domitian reached with the Dacian king Decebalus drew criticism from later writers who regarded its terms as shameful, yet it secured a measure of stability on that frontier. Many soldiers held a more favourable view of the emperor than senators did, so military loyalty and senatorial hostility could coexist.
Palace conspirators assassinated Domitian on 18 September AD 96. His official memory was condemned, and portraits and inscriptions were subsequently altered. Nerva, who succeeded him, pleased the Senate but met hostility from the Praetorian Guard. After fifteen years of his rule, the administration still functioned, but Domitian had alienated senators and faced a conspiracy within his palace.
4. Commodus (AD 177–192)
Commodus received the title of co-emperor alongside his father Marcus Aurelius in AD 177. When Marcus died in AD 180, he became sole ruler. Later writers measured his reign against that of his respected father. Commodus ended the prolonged campaigns his father had pursued on the Danube and agreed to peace. Scholars disagree whether that was a sensible settlement or a premature withdrawal; in practical terms, it freed him to return to Rome instead of commanding troops on the northern frontier for years.
Much of the governing power at court passed through influential favourites. The praetorian prefect Perennis and the freedman Cleander accumulated authority, while suspected conspirators and political enemies faced execution. An alleged plot involving Commodus’s sister Lucilla in AD 182 increased his mistrust. During food shortages and unrest in AD 190, Cleander was brought down in turn. Those court struggles shaped the administration alongside the public performances for which Commodus became notorious.
Commodus deliberately associated himself with Hercules, the mythical hero who defeated monstrous opponents. Portraits show the emperor in a lion skin, carrying the hero’s club. He also performed in the amphitheatre, killing animals and appearing as a gladiator. In Herodian’s account of the arena, Commodus shoots beasts from a protected platform, which kept him beyond their reach. Human challengers could scarcely treat a match against the emperor as an ordinary contest. The accounts give little reason to believe these were fairly matched contests in which he repeatedly risked his life.
These costly spectacles also offended Rome’s elite social hierarchy. Professional gladiators were considered low-status performers, so the participation of the emperor was especially offensive to aristocratic observers. Commodus also bestowed his own names and titles upon Rome, public institutions and the calendar. Coins and portraits portrayed him as a victorious figure of near-divine strength. Senatorial writers interpreted this imagery as personal self-glorification.
Late in AD 192, the emperor’s companion Marcia and palace officials came to believe that Commodus intended to kill them. Herodian 1.17 says a poisoning attempt failed before a wrestler named Narcissus strangled the emperor. His death opened another succession struggle: Pertinax briefly held power, only to be murdered by the Praetorian Guard, and rival candidates fought in the civil war of AD 193. The conflict was severe, but the imperial system survived under the eventual victor, Septimius Severus.
5. Elagabalus (AD 218–222)
Elagabalus came from a leading family in Emesa, a city in Roman Syria, and served there as priest of the god Elagabal. Born Varius Avitus Bassianus, he adopted the imperial name Marcus Aurelius Antoninus. His grandmother Julia Maesa helped instigate a revolt against Macrinus in AD 218, after Macrinus had succeeded the murdered emperor Caracalla. The rebels encouraged soldiers to believe that the adolescent priest was Caracalla’s son. The claim helped his bid for power, but no evidence securely establishes the relationship.
Once emperor, Elagabalus gave the Syrian god a prominent place in Rome. A dark, cone-shaped sacred stone associated with Elagabal was carried in public processions and placed in a temple on the Palatine. Herodian 5.5 records the young ruler’s priestly dress, elaborate offerings and elevation of the deity over others. The Roman world already accommodated many gods from across the Mediterranean. Observers feared that he meant to give the god he served priority over established Roman state cults.
His marriage to Aquilia Severa, one of the Vestal Virgins, caused particular outrage. The Vestals tended Rome’s sacred flame and were obliged to remain chaste, duties understood as bound to the city’s welfare. Ancient writers treated the marriage as a religious transgression. Their stories about the emperor’s sexuality, clothes and companions are much less securely established. The late Historia Augusta is notoriously unreliable, and descriptions of an effeminate, decadent or foreign ruler follow established conventions of hostile Roman biography.
Martijn Icks’s 2024 study of Elagabalus’s character assassination examines how accusations about his conduct were assembled into a hostile portrait of his reign. Icks notes the familiar stereotypes employed by the writers and the advantage gained by Severus Alexander’s new government in portraying its predecessor as intolerable. Some allegations may reflect events, but repetition in a hostile ancient account is not sufficient to verify claims about Elagabalus’s private conduct.
The Praetorian Guard eventually preferred Elagabalus’s younger cousin, the future Severus Alexander. In March AD 222 it killed Elagabalus and his mother, Julia Soaemias. Herodian 5.8 describes the mistreatment of their bodies and their disposal through a drain leading to the Tiber. Alexander continued the dynasty. The guards and palace had decided the succession by violence, while the administration survived. Alexander’s supporters also helped determine how Romans remembered the dead emperor.
6. Caracalla (AD 198–217)
Caracalla’s formal name, like that adopted by Elagabalus, was Marcus Aurelius Antoninus. He had been made co-emperor during the reign of his father Septimius Severus. After Severus died at York in AD 211, Caracalla and his younger brother Geta were supposed to govern together. Their mutual hostility made joint government impossible. Geta was killed in their mother’s presence by December, leaving Caracalla sole emperor. Cassius Dio, who wrote close to these events, and the later historian Herodian describe the killing as deliberate murder.
People connected with Geta were then hunted down. Herodian 4.6 describes the deaths of household attendants, associates and members of distinguished families. Ancient writers sometimes claim as many as 20,000 victims, a figure that cannot be independently verified. Geta’s portraits and inscriptions were also systematically altered or removed. Historians often use the term damnatio memoriae for this assault on a disgraced person’s memory, although traces of Geta could not be erased everywhere.
Caracalla was closely identified with the army. He raised soldiers’ pay and took the field on the northern frontiers and in the eastern provinces. His campaign at Alexandria became notorious for violence against its people; Herodian’s account attributes a massacre there to him, without providing a verifiable count of those killed. Higher military expenditure strained imperial resources. Yet his active campaigning and attention to military affairs make it inaccurate to picture him as an emperor who never engaged with government.
In AD 212, Caracalla proclaimed the Constitutio Antoniniana, granting citizenship to almost every free person living under Roman rule. The grant affected the legal position of free inhabitants across nearly the whole empire. The decree survives imperfectly in papyrus documents, and scholars still debate which groups, if any, were excluded. Cassius Dio connected the grant with the desire to increase tax revenue. Jussi Rantala’s 2023 study discusses the limitations of Dio’s senatorial interpretation, while Peter van Minnen’s reassessment of the papyrus shows why the surviving text cannot be reduced to a straightforward fiscal announcement.
A soldier assassinated Caracalla near Carrhae in April AD 217 during his campaign against Parthia. The praetorian prefect Macrinus succeeded him. Caracalla’s reign included his brother’s murder, the persecution of Geta’s supporters and military coercion, alongside sustained campaigning and a grant of citizenship that changed the empire’s legal landscape. The citizenship reform took place under a ruler also responsible for dynastic murder and political persecution.
7. Tiberius (AD 14–37)
When Augustus died in AD 14, Tiberius inherited the imperial position with decades of experience as a general and administrator. He was Rome’s second emperor and had to operate within a government that retained republican offices while placing effective authority in one ruler’s hands. His policy generally favoured maintaining the frontiers over launching large new conquests, and he conserved the imperial treasury. Regular state business continued despite the grim portrayal of his reign in later accounts.
The tension between Tiberius and the Senate increased as accusations of treason multiplied. The charge known as maiestas had originally concerned offences against the Roman people’s dignity and security, and came to protect the position of the emperor as well. Informers prosecuted alleged enemies, sometimes securing exile, execution or confiscation. In Tacitus’s account of the early reign, Tacitus describes fear at court alongside rivalries among senators that worsened the political climate.
Tiberius withdrew from Rome in AD 26 and eventually made the island of Capri his main residence. He still issued orders by correspondence, while Sejanus, the praetorian prefect, acquired tremendous influence in the capital. Political attacks increasingly struck the family of Germanicus. In AD 31 Tiberius turned unexpectedly against Sejanus and had him arrested and executed. Persecutions of Sejanus’s supporters followed. Orders still came from Capri, while the distance increased uncertainty in dealings among the palace, Senate and military authorities.
The evidence surrounding the death of Agrippina the Elder, Germanicus’s widow and Caligula’s mother, is particularly uncertain. She died while exiled in AD 33. Tacitus, Annals 6.25 leaves open whether she refused to eat or was denied food, so an order from Tiberius to starve her cannot be stated as an established fact. Tales of sexual excess during his residence on Capri should be assessed with comparable caution, particularly those found in Suetonius, who wrote long after the events.
Tiberius died in March AD 37 at the age of seventy-seven. Ancient rumours that the praetorian prefect Macro smothered him do not establish how he died. The empire he left behind had a functioning army and sound finances, while years of political prosecutions had damaged trust among Rome’s governing elite. The prosecutions shaped his reputation, although he remained an experienced administrator who kept the state functioning.
Each of these seven emperors became notorious for different reasons. Nero’s removal by rebellious military leaders led to civil war, and Commodus’s death was followed by another struggle over the throne. Caracalla murdered rivals yet granted citizenship on an extraordinary scale. Domitian and Tiberius kept much of the government working while their dealings with senators fostered lasting hostility. Elagabalus’s religious programme provoked genuine conflict, although accusations about his private life were greatly shaped by the conventions of hostile writers.
These hostile accounts also reveal how Roman imperial power operated. A ruler depended on senators, administrators, local populations and armies whose demands could contradict one another. After his death, those who survived had the opportunity to shape the narrative. Their accounts preserve real violence, but also rumours and the political language used to condemn a defeated ruler. Separating documented abuses from rumours helps explain why later Roman authors called these rulers the worst emperors.
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