The history of the Roman Empire is often associated with military conquest, monumental architecture, sophisticated administration, and some of antiquity’s most capable rulers. Yet its imperial system also produced emperors whose reigns exposed the dangers of concentrating political, military, and financial power in a single individual. From Caligula’s extravagant court to the final struggles of Constantinople, the failures of Rome’s rulers repeatedly weakened the institutions they were supposed to protect.
Some emperors became notorious for cruelty, executions, religious persecution, and personal extravagance. Others inherited collapsing frontiers, rival military commanders, or civil wars that no individual could easily resolve. Several accounts of their worst deeds, however, come from hostile ancient writers, political propaganda, or later legends. Distinguishing established events from sensational stories is essential to understanding what actually happened.
The following historical survey examines 18 Roman and Byzantine emperors whose reigns illustrate the consequences of tyranny, military overreach, political instability, and imperial decline. It spans the early Roman Empire, the Crisis of the Third Century, the collapse of the Western Empire, and the final fall of Constantinople in 1453.
1. Caligula (37–41 AD): The Emperor Who Turned Power Into Spectacle
Gaius Caesar, better known as Caligula, became Rome’s third emperor in 37 AD at approximately 24 years old. The son of the popular general Germanicus, he initially enjoyed enormous public goodwill. His early government offered signs of moderation, including public generosity and the restoration of certain political proceedings. His reputation changed dramatically after a severe illness later that year, although the claim that it fundamentally transformed his personality cannot be established with certainty.
Ancient historians, particularly Suetonius and Cassius Dio, portrayed Caligula as increasingly arbitrary, extravagant, and cruel. They accused him of humiliating senators, executing political opponents, and treating public office as an instrument of personal amusement. His relationships with his sisters, particularly Drusilla, also generated scandalous accounts, although the details remain disputed.
Caligula’s religious policies were controversial, especially his association with divine honors. Roman emperors could receive religious honors under particular circumstances, but demands that subjects treat a living emperor as a god could create serious political and cultural tensions. Stories that Caligula intended to make his favorite horse, Incitatus, a consul have become emblematic of his alleged contempt for the Senate. Whether he seriously intended to appoint the animal or merely used the threat to ridicule senators remains uncertain.
His financial policies also attracted criticism. He reportedly exhausted much of the surplus inherited from Tiberius through lavish spectacles, public distributions, construction projects, and court expenditure. Ancient estimates of imperial wealth and spending must be treated cautiously, particularly when they appear in hostile accounts.
On January 24, 41 AD, members of the Praetorian Guard and associated conspirators assassinated Caligula, ending his reign after less than four years. His death exposed a fundamental weakness in the early imperial system: the emperor possessed extraordinary authority, but his survival could depend on the loyalty of the very military personnel responsible for protecting him.
2. Nero (54–68 AD): Extravagance, Repression, and Civil War
Nero became emperor in 54 AD, aged approximately 16, following the death of his adoptive father, Claudius. His early government, influenced by the philosopher Seneca and the Praetorian prefect Burrus, was initially regarded more favorably than his later reputation suggests. Over time, however, political murders, court rivalries, extravagant spending, and conflicts with the Senate undermined his standing.
The Great Fire of Rome began in July 64 AD and devastated large portions of the city. Ten of Rome’s fourteen districts suffered damage, although only four reportedly escaped entirely unscathed. The familiar claim that Nero played a fiddle while Rome burned is anachronistic: the modern violin did not exist in antiquity. More importantly, no reliable evidence establishes that Nero deliberately started the fire. Tacitus, writing decades later, recorded competing accounts and noted Nero’s relief efforts.
Nero nevertheless used the aftermath to reshape parts of the city and construct the Domus Aurea, or Golden House, an immense palace complex incorporating landscaped grounds, artificial lakes, and elaborate architectural features. Its scale and extravagance became powerful symbols of imperial excess, especially when compared with the needs of Rome’s population.
Tacitus also describes Nero’s persecution of Christians after the fire, making them scapegoats for the disaster. Executions and other brutal punishments reportedly followed.
Nero’s family life was equally violent. His mother, Agrippina the Younger, was killed in 59 AD after an earlier attempt to murder her through a sabotaged vessel failed. His first wife, Octavia, was executed in 62 AD. His second wife, Poppaea Sabina, died in 65 AD, although the circumstances and Nero’s precise responsibility remain debated. Claims that he murdered every family member or executed senators simply to finance artistic pursuits are broader than the evidence supports.
In 68 AD, provincial rebellions and the loss of military support made his position untenable. Declared a public enemy by the Senate, Nero died by suicide in June. His fall ended the Julio-Claudian dynasty and triggered a civil war known as the Year of the Four Emperors.
3. Commodus (180–192 AD): The Emperor Who Made Himself a Gladiator
Commodus inherited the throne in 180 AD from his father, Marcus Aurelius, whose reign had become associated with military discipline and Stoic philosophy. Commodus’s accession marked the end of the period conventionally known as the era of the Five Good Emperors, although the idea that Rome’s decline began immediately afterward oversimplifies a much longer process.
Unlike his father, Commodus increasingly emphasized personal prestige, court spectacle, and identification with Hercules. His appearances as a gladiator in the arena shocked Rome’s political elite, who considered such performances beneath the dignity of an emperor. Ancient sources describe him fighting opponents and killing animals, although the precise number of appearances and the circumstances of individual performances remain uncertain.
Commodus reportedly demanded enormous payments for his appearances, placing additional pressure on the imperial treasury. He also renamed Rome Colonia Lucia Annia Commodiana and associated public institutions, the calendar, and the state with his own titles. These actions reflected a personality cult that alienated important members of the Senate.
His government became increasingly dependent on palace favorites, while conspiracies and purges intensified. The execution of political opponents and confiscation of property helped finance the court and eliminate potential rivals, but also deepened elite hostility.
On December 31, 192 AD, a conspiracy involving members of the imperial household arranged his assassination. Poison failed to kill him, and the wrestler Narcissus strangled him. Commodus’s death plunged the empire into another struggle for succession, demonstrating that personal rule without an accepted transfer of power could destabilize even a militarily powerful state.
4. Pertinax (193 AD): The Emperor Who Challenged the Praetorian Guard
Pertinax became emperor on December 31, 192 AD, following Commodus’s assassination. An experienced administrator and military commander, he attempted to restore financial discipline, rebuild confidence in government, and reverse some of the excesses associated with the previous reign.
His reforms placed him on a collision course with the Praetorian Guard, whose members expected substantial rewards for supporting a new emperor. Pertinax attempted to impose stricter discipline and could not satisfy the soldiers’ expectations of immediate financial compensation.
After only 86 days in power, he was murdered by Praetorian Guards on March 28, 193 AD. His assassination revealed how vulnerable an emperor could become when his closest military protectors withdrew their support.
The consequences extended far beyond the palace. The Praetorians subsequently offered the imperial position to the highest bidder, helping turn a succession crisis into a public demonstration of the military’s political power.
Pertinax was not a tyrant in the same sense as some emperors on this list. His importance lies in the failure of his reform program and the circumstances of his death, which exposed the weakness of imperial authority when it lacked reliable military backing.
5. Didius Julianus (193 AD): The Man Who Bought the Throne
Following Pertinax’s assassination, the Praetorian Guard effectively auctioned its support to competing candidates. Didius Julianus, a wealthy senator and former provincial administrator, emerged as the winner after offering substantial payments to the soldiers.
The episode became one of the most notorious examples of military interference in Roman succession. Ancient accounts differ in their descriptions of the bidding and the promised sums, so exact figures should not be treated as definitive. Nevertheless, the underlying event is well established: Julianus acquired the throne through an arrangement with the Praetorians rather than through a broad political or military consensus.
His position immediately deteriorated. Septimius Severus, commander of the legions in Pannonia, declared himself emperor and marched toward Italy. Other commanders, including Pescennius Niger in the eastern provinces and Clodius Albinus in Britain, also challenged the succession.
Julianus attempted negotiations and sought support from the Senate, but the Praetorian Guard could not match the forces advancing on Rome. The Senate recognized Severus and condemned Julianus, who was killed on June 1, 193 AD, after a reign of approximately 66 days.
His brief rule demonstrated that purchasing the loyalty of a palace guard was no substitute for commanding the provincial armies. It also helped establish a dangerous precedent: the empire’s supreme office could become the prize of competing military factions.
6. Septimius Severus (193–211 AD): The Rise of Military Monarchy
Septimius Severus emerged victorious from the civil wars that followed Pertinax’s death and founded the Severan dynasty. His reign restored a measure of stability after the upheaval of 193 AD, but his methods fundamentally strengthened the military at the expense of Rome’s traditional political institutions.
Severus defeated Pescennius Niger in the East and later eliminated Clodius Albinus after a bitter civil war. He reorganized the Praetorian Guard, replacing its traditional Italian recruitment base with soldiers drawn from his own provincial legions. He also increased military pay and rewarded the army with privileges and financial benefits.
These measures helped secure his throne, but they imposed a heavier burden on imperial finances. Future emperors increasingly faced the expectation that soldiers would receive larger payments, bonuses, and rewards in return for loyalty.
Severus also curtailed senatorial influence and relied on military officers and trusted administrators. The Senate remained an important institution, but its capacity to determine imperial succession or constrain the emperor continued to diminish.
While campaigning in Britain, Severus died at Eboracum, modern York, in February 211 AD. According to Cassius Dio, he advised his sons to enrich the soldiers and disregard everyone else. The familiar wording is a paraphrase of the ancient account rather than a securely preserved verbatim quotation.
Severus did not single-handedly cause Rome’s later crises. However, his government reinforced a system in which military loyalty became the principal foundation of imperial power, making succession disputes increasingly dangerous.
7. Caracalla (198–217 AD): Citizenship, Taxation, and Fratricide
Caracalla, born Lucius Septimius Bassianus, ruled alongside his father, Septimius Severus, and later his brother Geta. After Severus’s death, the brothers briefly shared power before Caracalla arranged Geta’s murder in December 211 AD. Ancient accounts describe Geta dying in the presence of their mother, Julia Domna, although details vary.
Caracalla subsequently ordered a massive purge of Geta’s supporters. Cassius Dio provides a particularly hostile account of the killings, describing widespread executions and confiscations. The scale of the violence is difficult to determine precisely, but the purge decisively eliminated the possibility of reconciliation between the brothers’ factions.
In 212 AD, Caracalla issued the Constitutio Antoniniana, extending Roman citizenship to nearly all free inhabitants of the empire, with certain exceptions. This was a major constitutional development that expanded the legal community of Roman citizens. The decree may also have broadened the tax base, although the claim that taxation was its sole or primary purpose is too simplistic.
Caracalla’s military campaigns, substantial pay increases for soldiers, and construction projects placed considerable demands on the treasury. His most famous building project, the Baths of Caracalla in Rome, became one of the largest public bathing complexes in the ancient world. It could accommodate thousands of visitors, although estimates of its simultaneous capacity vary.
In April 217 AD, Caracalla was assassinated near Carrhae while traveling in the eastern provinces. The plot involved the Praetorian prefect Macrinus, who subsequently became emperor. Caracalla’s death illustrates the continuing danger faced by rulers who depended on military loyalty while alienating political and personal rivals.
8. Elagabalus (218–222 AD): Religious Conflict and Court Scandal
Elagabalus became emperor in 218 AD at approximately 14 years old, following the defeat of Macrinus. Born Varius Avitus Bassianus, he had served as a hereditary priest of the Syrian sun deity Elagabal at Emesa. His accession brought a distinctive religious tradition into the center of Roman imperial politics.
He promoted the worship of Elagabal and established the deity’s cult at Rome, seeking to elevate it above traditional Roman religious practices. The initiative provoked opposition among members of the political elite, particularly because the emperor’s religious priorities challenged established customs and the prestige of Rome’s traditional gods.
Elagabalus’s personal life became the subject of sensational stories in ancient histories. Accounts describe multiple marriages, including a union with the Vestal Virgin Aquilia Severa. Such a marriage was deeply controversial because Vestal Virgins were bound by vows of chastity, and violating those vows traditionally carried severe religious and legal consequences.
Other allegations, including claims about sexual behavior, elaborate banquets, and extravagant palace entertainments, come largely from hostile literary sources. They should not be accepted uncritically as straightforward descriptions of events.
The emperor’s grandmother, Julia Maesa, eventually supported the elevation of his cousin Severus Alexander as a potential successor. As Elagabalus’s support collapsed, the Praetorian Guard turned against him.
In March 222 AD, Elagabalus and his mother, Julia Soaemias, were killed. Their bodies were reportedly subjected to indignities, and Elagabalus’s remains were thrown into the Tiber. His downfall demonstrated how quickly an emperor could lose power when his family, the army, and the capital’s political establishment withdrew their support.
9. Maximinus Thrax (235–238 AD): The Emperor of the Barracks
Maximinus Thrax became emperor in 235 AD after soldiers murdered Severus Alexander and his mother. His accession marked an important turning point: he was the first emperor whose rise is conventionally associated with the so-called barracks emperors, rulers whose authority rested primarily on military support rather than senatorial standing or established dynastic legitimacy.
Maximinus came from a provincial background and built his reputation through military service. Ancient writers describe him as exceptionally tall and physically powerful, but the more extravagant measurements and stories about his strength are not reliable enough to be treated as literal fact.
During his reign, Maximinus concentrated on frontier warfare, particularly campaigns along the Rhine and Danube. These operations required extensive resources, and the government imposed heavy financial demands on the population. Confiscations and extraordinary taxation helped pay for the army but alienated provincial elites and wealthy landowners.
In 238 AD, resistance began in North Africa, where local opposition to imperial taxation led to the proclamation of Gordian I and Gordian II. The Senate supported their revolt and declared Maximinus an enemy of the state.
Maximinus marched toward Italy but encountered resistance at Aquileia. While besieging the city, he was murdered by his own soldiers in May 238 AD, along with his son Maximus. His death contributed to a succession crisis known as the Year of the Six Emperors, illustrating the instability of a political system increasingly dominated by military force.
10. Gordian I (238 AD): The Reluctant Emperor
Gordian I was an elderly senator and provincial governor who became emperor during the uprising against Maximinus Thrax. His proclamation in Africa in 238 AD reflected widespread dissatisfaction with imperial taxation and the growing resentment of landowners and local elites.
Already advanced in age, Gordian accepted the imperial title alongside his son, Gordian II. Their joint claim offered an alternative to Maximinus and quickly gained recognition from the Senate in Rome.
Their position, however, depended on military success. Capellianus, the governor of Numidia, remained loyal to Maximinus and commanded experienced troops against the rebellion. The forces of Gordian II were defeated near Carthage, and Gordian II died in the fighting.
When Gordian I learned of his son’s death, he took his own life, according to the surviving historical accounts. Their joint reign lasted only about three weeks.
Gordian I’s brief imperial career shows how senatorial prestige and popular support could not guarantee survival during a military confrontation. In 238 AD, the imperial title changed hands repeatedly because no candidate could establish an uncontested claim to power.
11. Gordian II (238 AD): A Claim to Power Defeated on the Battlefield
Gordian II shared the imperial title with his father during the revolt against Maximinus Thrax. Unlike his elderly father, he took direct command of the forces intended to defend their new government in Africa.
His opponents were led by Capellianus, governor of Numidia, whose troops possessed greater military experience. The decisive battle near Carthage ended in defeat for the Gordian faction. Gordian II was killed, destroying the military foundation of the rebellion.
His death had immediate consequences. Gordian I, having lost his son and political partner, died by suicide shortly afterward. The Senate was forced to seek alternative candidates, eventually elevating Pupienus and Balbinus before the young Gordian III emerged as the eventual emperor.
The episode illustrates a recurring weakness in Roman political life: a claim to imperial legitimacy could collapse rapidly when it lacked an army capable of defending it. Gordian II was neither a long-reigning tyrant nor an architect of imperial decline. His significance lies in his role in the disastrous succession crisis of 238 AD.
12. Decius (249–251 AD): Religious Persecution and Defeat by the Goths
Decius became emperor in 249 AD after defeating Philip the Arab. His reign coincided with mounting pressure on Rome’s frontiers and an effort to reinforce traditional Roman religious practices.
In 250 AD, Decius issued an order requiring inhabitants of the empire to perform sacrifices to the Roman gods and obtain official documentation confirming their compliance. These certificates, known as libelli, survive in some cases through Egyptian papyri. The policy was not initially limited to Christians, but Christians who refused to sacrifice faced punishment, imprisonment, and, in some cases, execution.
The persecution was significant because it imposed an empire-wide religious requirement rather than relying exclusively on isolated local prosecutions. Nevertheless, the severity and implementation of the policy varied, and not every Christian who refused was executed.
Meanwhile, Decius faced renewed Gothic incursions across the Danube frontier. In 251 AD, he and his son, Herennius Etruscus, confronted Gothic forces at the Battle of Abritus, in what is now northeastern Bulgaria.
Both emperors died during the defeat, making Decius the first Roman emperor known to have been killed in battle against a foreign enemy. His death exposed the dangers of frontier warfare at a time when Rome was struggling to maintain military security and political continuity.
13. Valerian (253–260 AD): The Emperor Captured by Persia
Valerian became emperor in 253 AD during a period of political upheaval and intensified pressure on the empire’s eastern frontier. He initially shared power with his son Gallienus, who governed much of the West while Valerian concentrated on the conflict with the Sasanian Persian Empire.
The Persian king Shapur I launched major campaigns against Roman territory. In 260 AD, Valerian’s forces suffered a catastrophic defeat, and the emperor himself was captured by the Persians.
The capture was unprecedented in Roman imperial history. Unlike emperors who died in battle or were killed by conspirators, Valerian fell alive into the hands of a major foreign power.
Shapur’s inscriptions commemorate the victory, while later accounts describe Valerian being humiliated in captivity. Lactantius, a Christian author writing considerably later, claimed that Shapur used the emperor as a footstool when mounting his horse and that Valerian’s skin was preserved as a trophy after his death. Other sensational stories allege that he was killed through particularly degrading methods.
These details cannot all be independently verified. The precise circumstances of Valerian’s death remain unknown, although he did not return to Roman territory.
His capture weakened Roman authority in the East and damaged the prestige of the imperial office. It also demonstrated the growing ability of the Sasanian state to challenge Rome as a major military power.
14. Gallienus (253–268 AD): An Empire Fragmented by Crisis
Gallienus became co-emperor with Valerian in 253 AD and ruled alone after his father’s capture in 260 AD. His reign coincided with one of the most dangerous periods in Roman history, commonly known as the Crisis of the Third Century.
Military defeats, economic disruption, epidemics, and repeated usurpations placed the empire under enormous pressure. In the West, the Gallic Empire emerged under Postumus, controlling territories that included Gaul and, at various times, Britain and parts of Hispania. In the East, the Palmyrene leadership under Odaenathus and later Zenobia established increasingly independent control over substantial eastern territories.
The empire did not formally divide into three permanently sovereign states, but central authority weakened dramatically. Gallienus struggled to maintain control while responding to invasions and rival claimants.
Despite these difficulties, he introduced important military changes. He strengthened the role of mobile cavalry forces and relied increasingly on professional military commanders. His government also reduced the Senate’s traditional role in military command, reflecting the practical demands of fighting wars across multiple frontiers.
Gallienus was killed in 268 AD during a campaign against the usurper Aureolus near Milan. His assassination by members of his own military establishment reflected the continuing instability of imperial succession.
Although later accounts sometimes present Gallienus as a failed ruler, his military reforms helped prepare the way for the restoration of imperial unity under Claudius II, Aurelian, and subsequent emperors.
15. Honorius (395–423 AD): The Sack of Rome
Honorius became Western Roman emperor in 395 AD at approximately ten years old, following the death of Theodosius I. His reign coincided with the accelerating fragmentation of the Western Empire, as military pressures, political rivalries, and the loss of provincial territory undermined the government’s authority.
For much of the early reign, the general Stilicho exercised considerable influence over Western imperial policy. He attempted to manage relations with the Visigoths and defend the empire against invasions, but his position became increasingly vulnerable to court intrigue. In 408 AD, Honorius ordered Stilicho’s execution, removing one of the most experienced commanders available to the Western government.
The consequences were severe. The Visigothic king Alaric continued to pressure the empire, eventually entering Rome and sacking the city on August 24, 410 AD. It was the first time in approximately eight centuries that Rome had been captured and plundered by a foreign army.
The sack shocked the Roman world, although Rome was no longer the Western Empire’s principal imperial residence. Honorius governed from Ravenna, a city better protected by its geography and defenses.
A famous anecdote, preserved by the historian Procopius in the sixth century, claims that Honorius mistakenly thought a report that “Rome” had perished referred to his favorite chicken of the same name. The story is generally regarded as unreliable and possibly satirical.
Honorius’s government also witnessed the effective loss of Roman control over Britain and increasing territorial fragmentation in Gaul and Hispania. He died in 423 AD, leaving a Western Empire weakened by decades of political and military failure.
16. Valentinian III (425–455 AD): The Murder of Rome’s Greatest General
Valentinian III became Western Roman emperor in 425 AD at approximately six years old. His mother, Galla Placidia, initially exercised considerable influence over the government, while the empire relied increasingly on powerful generals to manage military affairs.
The most influential of these commanders was Flavius Aetius, who spent years attempting to preserve Roman authority in Gaul and defend the empire against external threats. In 451 AD, Aetius played a central role in the coalition that confronted Attila’s Huns at the Battle of the Catalaunian Plains.
Although the battle’s precise outcome and its strategic consequences remain debated, Aetius was one of the Western Empire’s most capable military leaders.
His relationship with Valentinian deteriorated, and in September 454 AD the emperor personally killed him during a confrontation at court. The decision eliminated a powerful commander at a time when the empire had few comparable military resources.
On March 16, 455 AD, supporters associated with Aetius assassinated Valentinian. The emperor’s death created another succession crisis, further weakening the already fragile Western government.
In June 455 AD, the Vandals under King Genseric entered Rome and sacked the city. The Vandals had already established control over much of North Africa, including Carthage, a major source of Western imperial revenue.
Valentinian did not single-handedly cause the Western Empire’s collapse, but his murder of Aetius and his own subsequent assassination contributed to a political breakdown from which the Western government never recovered.
17. Romulus Augustulus (475–476 AD): The Last Western Roman Emperor
Romulus Augustulus became Western Roman emperor in 475 AD, installed by his father, the military commander Orestes. His precise age is uncertain, although he was probably a young teenager. The name Augustulus, meaning “little Augustus,” became an enduring symbol of the contrast between the grandeur of Rome’s first emperor and the weakness of its final Western ruler.
Orestes exercised the real power, but his government struggled to satisfy the demands of Germanic troops serving in Italy. In 476 AD, the military leader Odoacer led a revolt against Orestes, defeated his forces, and captured Ravenna.
Romulus was deposed on September 4, 476 AD. Unlike many displaced emperors, he was reportedly spared execution and granted a pension, traditionally associated with an estate in Campania. His later life is poorly documented.
The Eastern Roman government at Constantinople did not recognize Romulus as a legitimate emperor, and the deposition did not mean that the Roman Empire ceased to exist everywhere. Odoacer ruled Italy while nominally acknowledging the Eastern emperor’s authority, and the Eastern Roman Empire continued for almost another thousand years.
Nevertheless, 476 AD remains the conventional date for the fall of the Western Roman Empire. The event reflected a prolonged process involving territorial losses, military dependence, fiscal decline, and political fragmentation rather than a sudden collapse caused by one emperor.
Romulus Augustulus was more a symbol of the Western Empire’s final weakness than its architect. The institutions that had sustained Roman rule in the West had been eroding for generations before his brief reign.
18. Phocas (602–610 AD): A Usurper Who Nearly Destroyed the Eastern Empire
Phocas was a military officer who seized power in 602 AD after a rebellion against Emperor Maurice. Maurice had attempted to impose unpopular military demands, including requiring troops to campaign under difficult conditions without the expected relief and supplies. The revolt that followed culminated in Maurice’s overthrow and execution.
Phocas’s accession marked a violent break in imperial continuity. Maurice and his sons were killed, and the new emperor faced opposition from sections of the military and aristocracy. His government relied heavily on repression, executions, and coercion to suppress challenges to his authority.
The greatest danger came from the Sasanian Persian Empire. King Khosrow II used Maurice’s overthrow as a pretext for war, launching an invasion that developed into a devastating conflict. Persian forces captured major cities and conquered extensive Byzantine territory, including Jerusalem in 614 AD and Egypt in 619 AD. These conquests occurred after Phocas’s reign, but the conflict began under his government.
In 608 AD, Heraclius, the governor of Africa, rebelled against Phocas. His son, also named Heraclius, sailed toward Constantinople with forces in 610 AD. Phocas was overthrown and executed, and Heraclius assumed the throne.
Phocas’s reign had severely weakened the empire’s political stability at a moment when it faced a major external threat. However, the subsequent Persian invasions and the empire’s later territorial losses cannot be attributed solely to him; they resulted from a broader military and geopolitical crisis.
19. Justinian II (685–695; 705–711 AD): The Emperor Who Returned for Revenge
Justinian II ruled the Byzantine Empire in two separate periods, first from 685 to 695 AD and again from 705 to 711 AD. His reigns were marked by fiscal pressure, military challenges, and fierce conflicts with political opponents.
During his first reign, Justinian pursued ambitious administrative and fiscal policies while attempting to strengthen imperial authority. His methods generated opposition among military commanders and influential elites. In 695 AD, a rebellion overthrew him, and he was mutilated by having his nose cut off before being exiled. The mutilation was intended to prevent his return to the throne, reflecting the Byzantine belief that a physically disfigured man was unsuitable for imperial office.
Justinian nevertheless survived in exile and eventually secured support from foreign allies. In 705 AD, he returned with an army and regained Constantinople, beginning a second reign driven in part by a desire for retribution.
His restoration was followed by executions and reprisals against opponents. The regime’s coercive methods alienated important groups within the empire, while military reverses further weakened his position.
In 711 AD, a rebellion led by forces associated with the military commander Bardanes, who became Emperor Philippicus, ended Justinian’s second reign. Justinian and his young son Tiberius were killed.
Justinian II’s career illustrates the dangers of personal vengeance in imperial government. His ability to reclaim the throne demonstrated the importance of alliances and military support, but his failure to rebuild a durable political coalition ensured that his restoration would be short-lived.
20. Constantine XI Palaiologos (1449–1453 AD): The Last Emperor of Constantinople
Constantine XI Palaiologos became emperor in 1449, inheriting an empire that had long since lost most of its former territories. By the fifteenth century, the Byzantine state consisted principally of Constantinople and a handful of remaining possessions. The Ottoman Empire, by contrast, had become a major regional power under Sultan Mehmed II.
When Mehmed began his siege of Constantinople on April 6, 1453, Constantine faced overwhelming odds. The city possessed formidable defensive walls, but its defenders were limited in number, and the empire lacked the manpower and resources to match the Ottoman army.
Mehmed deployed large artillery pieces, including enormous bombards capable of battering the city’s ancient fortifications. Ottoman forces attacked the land walls repeatedly while naval operations and the blockade restricted the defenders’ ability to receive supplies and reinforcements.
Constantine sought assistance from Western Christian powers, but the support that arrived was insufficient to break the siege. The defense included Byzantine troops and foreign volunteers, notably Genoese soldiers under Giovanni Giustiniani.
On May 29, 1453, Ottoman forces breached the defenses and entered Constantinople. Constantine reportedly joined the final fighting and died during the city’s fall. His body was never conclusively identified, and many later stories about his final words or precise death circumstances remain legendary rather than firmly documented.
The capture of Constantinople ended the Byzantine Empire, the medieval continuation of the Eastern Roman state. Unlike the emperors associated with cruelty or reckless extravagance, Constantine XI is generally remembered for attempting to defend his capital against an overwhelmingly powerful enemy.
His death represents a very different kind of imperial failure from the reigns of Caligula, Commodus, or Phocas. Constantine did not inherit a thriving empire that he personally destroyed; he inherited a diminished state confronting a military challenge that its remaining resources were scarcely capable of meeting.
What These Emperors Reveal About Rome’s Decline
The history of Rome cannot be reduced to a succession of mad, cruel, or incompetent emperors. Its rise and fall involved changing economic conditions, military pressures, administrative reforms, political institutions, and relations with neighboring states. Nevertheless, the emperors examined here reveal several recurring weaknesses in the imperial system.
First, succession remained a persistent source of instability. Caligula, Commodus, Pertinax, and Didius Julianus all died amid political violence or succession crises. Without a consistently accepted method of transferring power, the death or overthrow of an emperor could trigger civil war.
Second, military loyalty increasingly determined political survival. Septimius Severus strengthened the army’s position, while the events of 193 and 238 AD demonstrated how readily soldiers could elevate or overthrow emperors. During the third century, rival generals repeatedly claimed the throne, often weakening the empire’s ability to defend its borders.
Third, financial pressures magnified political mistakes. Military pay, civil wars, public construction, and extravagant courts placed demands on imperial revenues. Excessive taxation and confiscations could alienate the very provincial elites and taxpayers on whom the government depended.
Fourth, personal rule could become dangerous when institutions failed to impose restraints. The worst accounts of Caligula, Nero, and Commodus describe rulers who used state power to satisfy personal ambitions or punish perceived enemies. Although ancient sources sometimes exaggerated their misconduct, the underlying political problem was real: the emperor possessed extraordinary authority, and the institutions capable of restraining him were often weak.
Finally, the Western Empire’s collapse and the Byzantine Empire’s eventual fall were not the same event. The Western imperial government ended in 476 AD, while the Eastern Roman state survived until 1453 AD. Its longevity demonstrates that Roman institutions could adapt and endure despite repeated military defeats, political crises, and territorial losses.
The central lesson is not simply that bad emperors destroyed Rome. Rather, Rome became most vulnerable when personal ambition, military power, fiscal weakness, and political instability reinforced one another. Some emperors accelerated those problems through their own decisions; others inherited crises they could not overcome. Understanding the difference is essential to an accurate history of one of the world’s longest-lasting imperial traditions.
