What If Caligula Completed His Full Reign?

The Actual History

Gaius Julius Caesar Augustus Germanicus, better known by his childhood nickname "Caligula" (meaning "little boot"), ruled as Roman Emperor from 37 to 41 CE. His brief reign, lasting just under four years, has become synonymous with tyranny, excess, and mental instability, though modern historians debate how much of his negative portrayal reflects historical reality versus posthumous propaganda.

Born in 12 CE to the popular general Germanicus and Agrippina the Elder, Caligula spent his early years accompanying his father on military campaigns—hence the nickname given to him by soldiers when he wore a miniature military uniform as a child. After his father's suspicious death in 19 CE, Caligula lived first with his mother until her exile, then with his great-grandmother Livia, and finally with his grandmother Antonia Minor. During the reign of Emperor Tiberius, Caligula's family suffered greatly, with his mother and two brothers dying in exile or imprisonment. Caligula himself was summoned to the emperor's retreat on Capri in 31 CE, where he remained until Tiberius's death in 37 CE.

Caligula's accession to power at age 24 was initially met with widespread jubilation. As the son of the beloved Germanicus, he represented a connection to the popular Augustus rather than the increasingly reclusive and mistrusted Tiberius. The early months of his reign seemed to confirm these positive expectations. He recalled exiles, eliminated an unpopular tax, and provided lavish public entertainments. He also publicly destroyed Tiberius's treason records, seemingly signaling an end to the climate of fear that had characterized his predecessor's later years.

However, in late 37 or early 38 CE, Caligula fell seriously ill. Ancient sources suggest this illness marked a turning point, after which his behavior became increasingly erratic and tyrannical, though modern historians debate whether this represented an actual mental breakdown or simply a shift toward more assertive governance that was later exaggerated by hostile sources.

The remainder of Caligula's reign was characterized by a series of controversial actions and policies:

He executed or forced the suicide of several prominent Romans, including his cousin and adopted son Tiberius Gemellus, his father-in-law Marcus Junius Silanus, and the praetorian prefect Macro who had helped him secure power.
He engaged in a series of rapid marriages and divorces, most notoriously taking his sister Drusilla as a lover according to some sources, and proclaiming her a goddess after her death in 38 CE.
He conducted brief and possibly staged military campaigns, most famously ordering troops to collect seashells as "spoils of the ocean" during a planned invasion of Britain that never materialized.
He implemented unusual and provocative religious policies, including declaring himself a living god and planning to install a statue of himself in the Temple in Jerusalem.
He auctioned the lives and property of gladiators at shows, forced senators' wives into prostitution (according to Suetonius), and allegedly planned to make his horse, Incitatus, a consul.
He depleted the imperial treasury through extravagant spending on games, spectacles, and architectural projects, including two massive ships on Lake Nemi that were essentially floating palaces.

Caligula's increasingly antagonistic relationship with the Senate culminated in a conspiracy led by officers of the Praetorian Guard. On January 24, 41 CE, he was assassinated while attending the theater. The conspirators, led by the tribune Cassius Chaerea (whom Caligula had reportedly humiliated with sexual taunts), stabbed the emperor multiple times. His wife Caesonia and infant daughter Julia Drusilla were also killed.

In the chaotic aftermath of the assassination, the Praetorian Guard found Caligula's uncle Claudius hiding behind a palace curtain and proclaimed him emperor. Despite initial reluctance from the Senate, Claudius secured his position and went on to rule for 13 years, proving more capable than his contemporaries expected.

Caligula's memory was subjected to damnatio memoriae (condemnation of memory), with his statues destroyed or reworked and his name erased from many public inscriptions. His brief reign was portrayed by ancient historians Suetonius, Cassius Dio, and others as an example of the worst excesses of imperial power, though these accounts were written decades or even centuries later and relied on potentially biased sources.

Modern historians have questioned aspects of the traditional portrayal, suggesting that some of Caligula's "madness" may have been deliberate provocation of the senatorial class, misunderstood religious or political symbolism, or posthumous exaggeration. Nevertheless, his assassination established a dangerous precedent of military involvement in imperial succession and demonstrated the vulnerability of even the most powerful emperor to conspiracy and violence.

The Point of Divergence

What if Caligula had avoided assassination in 41 CE and completed a full reign of several decades? What if, instead of being murdered at age 28 after less than four years in power, he had lived to old age like Augustus, ruling the Roman Empire for thirty or forty years?

In this alternate timeline, let's imagine that the conspiracy led by Cassius Chaerea failed or never materialized. Perhaps Caligula discovered the plot through his network of informants and executed the conspirators. Or maybe key figures like Chaerea were won over to the emperor's side through promotions or other favors. Alternatively, we might envision that Caligula's Praetorian Guard remained more consistently loyal, perhaps due to more generous donatives or because the emperor had appointed more personally loyal officers to key positions.

With the immediate threat removed, Caligula would have continued his reign beyond January 41 CE. His uncle Claudius would never have become emperor, and the succession would have followed a different path. Caligula, who was only 28 at the time of his historical assassination, could potentially have ruled for decades, dying of natural causes in his 60s or 70s sometime in the 70s or 80s CE.

This extended reign would have given Caligula time to develop as a ruler, potentially moving beyond the erratic behavior of his early years. It would also have allowed him to implement more lasting policies and to address the question of succession—perhaps by having additional children or by adopting and grooming a successor of his choice.

This alternate history explores how the Roman Empire might have developed under decades of Caligula's rule rather than the brief, chaotic interlude it represented historically. Would the young emperor have moderated his behavior over time, perhaps evolving into a more conventional ruler? Or would his tyrannical tendencies have intensified, creating an even more autocratic imperial model than that established by his successors? How would a long Caligulan reign have affected the development of the early Empire's institutions, the spread of Christianity, and the Empire's relationships with its provinces and neighbors? And how might the subsequent history of Rome have unfolded with a different imperial succession, bypassing Claudius and Nero entirely?

Immediate Aftermath

Political Stabilization

The immediate consequence of Caligula's survival would have been a period of political realignment as the imperial court and Roman elite adjusted to the reality of his continued rule:

Purge of Opponents: Having survived an assassination attempt, Caligula would likely have initiated a thorough purge of real and suspected opponents. The immediate conspirators would have been executed in public and humiliating ways, but the investigation would probably have extended more broadly, potentially implicating senators, equestrians, and military officers with tenuous connections to the plot.
Praetorian Guard Reorganization: The Praetorian Guard, from which the historical conspiracy emerged, would have undergone significant restructuring. Caligula might have executed or dismissed suspect officers, recruited new guards from his Germanic bodyguards (who were historically more loyal to him), and implemented stricter loyalty tests and surveillance within the guard.
Senate Intimidation: The relationship between Caligula and the Senate, already strained, would have deteriorated further. Surviving a plot would have confirmed Caligula's suspicions about senatorial hostility, potentially leading to more senators being forced to suicide or executed on treason charges. The Senate might have been further sidelined as a governing body, reduced to a ceremonial role earlier than occurred historically.
Court Politics: The imperial court would have become increasingly important as the center of power, with influence determined by personal access to the emperor rather than traditional institutional roles. Caligula's sisters, particularly Agrippina the Younger and Julia Livilla (who were historically recalled from exile by Claudius), might have played significant roles in court politics if reconciled with their brother.

Governance Approach

With his position secured, Caligula's approach to governance might have evolved in several possible directions:

Autocratic Consolidation: The failed assassination attempt might have accelerated Caligula's move toward more explicit autocracy, abandoning the Augustan pretense of being "first citizen" in favor of more eastern-style absolute monarchy. His reported interest in divine honors and eastern royal practices might have intensified.
Administrative Development: Despite his erratic reputation, Caligula showed some administrative competence early in his reign. With more time, he might have developed a more systematic approach to governance, potentially creating new administrative structures less dependent on senatorial cooperation.
Potential Moderation: Alternatively, surviving an assassination attempt might have served as a wake-up call, potentially leading to a moderation of Caligula's most provocative behaviors. Historical examples exist of rulers who began tyrannically but became more measured over time as they secured their position.
Provincial Focus: Caligula showed interest in the provinces, planning campaigns in Britain and Germany and considering moving to Alexandria at one point. He might have shifted focus away from Rome itself, spending more time in provincial capitals and addressing provincial administration more directly than his predecessors.

Economic Policies

Caligula's economic approach would have had significant implications for the empire's finances:

Fiscal Challenges: By 41 CE, Caligula had reportedly depleted the treasury surplus left by Tiberius. A continuing reign would have faced immediate fiscal challenges, requiring new revenue sources or spending reductions.
Taxation and Confiscation: To address financial needs, Caligula might have increased taxation, particularly in the provinces, and continued or expanded the use of treason charges to confiscate wealthy Romans' estates.
Infrastructure Investment: Despite his reputation for wasteful spending, Caligula initiated several practical infrastructure projects, including aqueducts, harbors, and roads. A longer reign might have seen more such projects, potentially with economic benefits offsetting their costs.
Economic Innovation: Facing fiscal pressures, Caligula might have experimented with economic innovations. His brief reign already showed willingness to try unconventional approaches, such as auctioning gladiatorial equipment and attempting to tax lawsuits.

Military Affairs

Caligula's continued reign would have had significant military implications:

British Invasion: The invasion of Britain, which Caligula historically prepared but abandoned, might have proceeded. This could have brought Britain into the Empire decades earlier than under Claudius, potentially with a different pattern of conquest and settlement.
Germanic Campaigns: Caligula might have pursued more substantial campaigns against Germanic tribes, potentially altering the Empire's northern frontier. His personal connection to the Rhine legions through his childhood might have made this frontier a particular focus.
Military Leadership: Caligula's approach to military leadership might have evolved with experience. His early attempts at military glory were somewhat theatrical, but a longer reign might have seen the development of more substantive military policies or the emergence of capable generals under his patronage.
Army Loyalty: Ensuring the loyalty of the legions would have been crucial after surviving a Praetorian plot. Caligula might have increased military pay, provided more frequent donatives, or implemented loyalty measures within the army's command structure.

Cultural and Religious Developments

Caligula's religious policies and cultural patronage would have left a more substantial mark on Roman society:

Imperial Cult Evolution: Caligula's interest in divine honors might have accelerated the development of the imperial cult, potentially creating a more direct form of emperor worship within Rome itself rather than just in the provinces.
Religious Conflicts: His reported plan to place a statue of himself in the Temple in Jerusalem, which nearly caused a Jewish revolt historically, might have proceeded, potentially triggering significant religious conflicts in Judea decades before the First Jewish-Roman War of 66-73 CE.
Architectural Legacy: With a longer reign, Caligula's architectural projects would have been more numerous and completed rather than left to successors. His reported interest in ambitious building projects might have transformed Rome's urban landscape.
Cultural Patronage: Caligula's theatrical interests might have influenced Roman cultural development. He was known to favor pantomime and other performance arts that were sometimes looked down upon by the elite, potentially elevating their status in Roman culture.

Succession Planning

As his reign progressed, the question of succession would have become increasingly important:

Dynastic Continuation: Caligula's daughter Julia Drusilla (who was killed as an infant in our timeline) might have lived, potentially becoming a dynastic link. Caligula might have had additional children who could have been groomed as heirs.
Adoption Possibilities: Without biological sons, Caligula might have eventually adopted a successor, potentially selecting from among relatives like his cousin Nero (son of Agrippina the Younger, who became emperor historically) or from promising non-relatives.
Female Succession: Given Caligula's close relationship with his sisters, he might have considered a female succession through one of them or their children, which would have been unprecedented in Rome but not in some eastern kingdoms.
New Dynastic Alliances: Through marriage alliances for himself or family members, Caligula might have created new dynastic connections, potentially incorporating provincial elites or even foreign royalty into the imperial family.

The immediate aftermath of Caligula's survival would have represented a critical juncture in Roman imperial development. The Julio-Claudian dynasty would have continued along a different line, the relationship between emperor and traditional institutions would have evolved differently, and the precedent of successful assassination that historically shaped imperial politics would not have been established so early in the Empire's history. While Caligula's rule might have been challenging for many Romans, particularly the senatorial elite, it would have provided greater continuity in the early imperial period and potentially allowed for the development of more stable imperial institutions.

Long-term Impact

Evolution of Imperial Authority

A decades-long Caligulan reign would have fundamentally altered the development of imperial power and its relationship to traditional Roman institutions:

Accelerated Autocracy: The Augustan model of disguised monarchy—maintaining republican facades while exercising monarchical power—might have given way more quickly to explicit autocracy. Caligula's reported interest in eastern-style kingship and divine honors suggests he might have moved the Empire toward a more openly absolutist model decades before Domitian or Diocletian attempted similar transformations.
Institutional Reconfiguration: The traditional republican institutions, particularly the Senate, might have been more thoroughly marginalized or transformed. Rather than the gradual evolution that occurred historically, where the Senate retained significant prestige and some practical functions for centuries, a long Caligulan reign might have accelerated its reduction to a purely ceremonial body.
New Administrative Structures: Without the Senate as an effective governing partner, Caligula might have developed alternative administrative structures earlier than occurred historically. The imperial bureaucracy, staffed by freedmen and equestrians rather than senators, might have expanded more rapidly, creating a more centralized and professional administration.
Imperial Accessibility: Caligula's reported willingness to interact directly with the plebeian population of Rome, bypassing traditional aristocratic intermediaries, might have established a different model of imperial accessibility. This could have created a more direct relationship between emperor and populace, potentially with both populist and autocratic implications.

Social and Cultural Transformation

Roman society and culture would have developed along significantly different lines under extended Caligulan influence:

Elite Composition: The traditional senatorial elite would likely have faced sustained pressure, with periodic purges and property confiscations. This might have accelerated the replacement of the old republican nobility with a new elite defined by personal loyalty to the emperor rather than ancient lineage.
Cultural Priorities: Caligula's known interests in spectacles, chariot racing, and theatrical performances might have elevated these cultural forms to greater prominence. The cultural priorities of the Empire might have shifted more decisively away from the literary and philosophical traditions valued by the senatorial elite toward more popular entertainments.
Architectural Legacy: With decades to build rather than just years, Caligula's architectural imprint on Rome and the Empire would have been substantial. His reported interest in ambitious and innovative projects might have transformed Rome's urban landscape and influenced architectural development throughout the Empire.
Religious Evolution: Caligula's approach to religion, which seemed to involve both sincere interest in certain cults and provocative manipulation of religious symbols, might have significantly altered Roman religious development. The imperial cult might have taken a more direct form, while traditional Roman religion might have incorporated more eastern elements.

Military and Territorial Development

The Empire's military organization and territorial extent would have reflected Caligula's priorities and decisions over decades:

Frontier Policy: Caligula's frontier policy might have differed significantly from the historical pattern. His personal connection to the Rhine legions might have made the Germanic frontier a particular focus, potentially leading to more aggressive expansion in this region rather than the generally defensive stance adopted historically.
British Conquest: Britain, which Caligula prepared to invade historically before abandoning the campaign, might have been conquered decades earlier than under Claudius. This earlier incorporation into the Empire would have allowed for longer Romanization, potentially creating a more thoroughly integrated province.
Military Organization: The organization and command structure of the Roman military might have evolved differently. Caligula's reported suspicion of successful generals might have led to more frequent rotation of commands or greater direct imperial involvement in military affairs, altering the relationship between emperor and army.
Eastern Relations: Caligula showed interest in eastern affairs, particularly regarding client kingdoms. His approach to these relationships, which seemed to involve more direct intervention than his predecessors, might have accelerated the conversion of client kingdoms into provinces or created different patterns of Roman-client relations.

Economic and Fiscal Policies

The economic structure of the Empire would have developed differently under long-term Caligulan management:

Fiscal Innovation: Facing the depletion of the treasury surplus left by Tiberius, Caligula would have needed to develop sustainable fiscal policies for the long term. This necessity might have driven innovative approaches to taxation, trade regulation, or monetary policy.
Infrastructure Investment: Despite his reputation for wasteful spending, Caligula initiated several practical infrastructure projects. A longer reign might have seen the completion of an extensive infrastructure program, potentially including the Rhegium-Messina bridge he reportedly considered, with significant economic implications.
Wealth Distribution: Caligula's reported willingness to confiscate senatorial property while being generous to the plebeian population might have created different patterns of wealth distribution, potentially reducing the extreme concentration of wealth that characterized the early Empire.
Provincial Economic Integration: With more time to develop coherent policies, Caligula might have addressed provincial economic integration more systematically. His interest in the provinces, particularly Egypt and Gaul, suggests he might have pursued policies that altered the economic relationship between Italy and the provinces.

Religious Developments and Early Christianity

The religious landscape, including the emerging Christian movement, would have evolved differently:

Imperial Cult Transformation: Caligula's apparent interest in receiving divine honors during his lifetime rather than posthumously might have transformed the imperial cult into a more direct form of emperor worship. This could have created different religious dynamics throughout the Empire.
Jewish Relations: Caligula's reported plan to place his statue in the Jerusalem Temple, which nearly caused a revolt historically, might have proceeded. This could have triggered the Jewish-Roman conflicts decades earlier than historically occurred, potentially with different outcomes.
Early Christianity: The early Christian movement, still in its formative stages during Caligula's reign, might have developed very differently. A major Jewish-Roman conflict during this period could have affected the relationship between Jewish and Gentile Christians, while a more explicitly divine emperor might have created clearer lines of religious conflict for the emerging faith.
Religious Syncretism: Caligula's interest in eastern cults and willingness to experiment with religious forms might have accelerated religious syncretism in the Empire, potentially creating new hybrid religious forms that incorporated elements from multiple traditions.

Succession and Dynasty

The imperial succession would have followed a completely different path, with far-reaching consequences:

Altered Julio-Claudian Line: Claudius would never have become emperor, and Nero (who was Caligula's cousin and Agrippina's son) might have had a completely different career, perhaps as Caligula's heir or perhaps as a victim of his suspicion. The Julio-Claudian dynasty would have continued along a different line.
New Succession Patterns: Caligula might have established different patterns of succession than those that developed historically. If he favored biological succession through a daughter, adopted heirs from outside the family, or created new dynastic connections through marriage, the principles of imperial succession might have evolved differently.
Flavian Fate: The Flavian dynasty (Vespasian, Titus, Domitian) that historically followed the Julio-Claudians might never have risen to prominence. Vespasian's early career occurred during Caligula's reign, and a different imperial trajectory might have led him and his sons down entirely different paths.
Long-term Stability: The question of whether a longer Caligulan reign would have created more or less dynastic stability is complex. While avoiding the rapid succession of the historical Julio-Claudian period might have provided more continuity, Caligula's reported volatility might have created different forms of instability.

Intellectual and Legal Development

The intellectual climate and legal system would have reflected Caligulan influence over decades:

Intellectual Freedom: Caligula's reported hostility toward independent-minded senators and his interest in controlling expression might have created a more restrictive intellectual climate. This could have affected philosophical development, historical writing, and literary production.
Legal Evolution: Roman law might have evolved differently under extended Caligulan influence. His apparent willingness to make arbitrary legal decisions might have undermined the development of consistent legal principles, or alternatively, might have led to legal reforms that centralized authority more explicitly.
Historical Memory: The historical record itself would be dramatically different. Instead of being remembered as a brief aberration between the more substantial reigns of Tiberius and Claudius, Caligula would have been one of Rome's longest-ruling and most influential emperors, potentially with a more nuanced historical assessment.
Educational Patterns: The education of the Roman elite, traditionally focused on preparing young men for senatorial careers, might have evolved differently if the Senate's importance declined more rapidly. New educational priorities might have emerged, focused on imperial service rather than republican traditions.

Counterfactual Considerations

While imagining this alternate timeline, several important factors must be considered:

Psychological Development: Caligula was only 28 at the time of his historical assassination. His reported erratic behavior might have been a phase rather than a permanent condition. Many rulers who began tyrannically moderated over time, and Caligula might have matured into a more stable leader.
Health Factors: Caligula suffered a serious illness early in his reign that some historians connect to his behavioral changes. If this represented an ongoing health condition, it might have affected his long-term capacity to rule effectively or even his lifespan.
External Pressures: The Roman Empire faced ongoing external challenges that would have shaped Caligula's reign regardless of his personal inclinations. Frontier pressures, provincial administration needs, and economic realities would have imposed certain constraints and necessities.
Institutional Resilience: Roman institutions had demonstrated considerable resilience and adaptability. Even under a potentially autocratic emperor like Caligula, these institutions might have found ways to adapt and continue functioning, potentially moderating the most extreme tendencies of the ruler.

In this alternate timeline, the history of the Roman Empire—and by extension, of Western civilization—would have followed a fundamentally different path. The particular balance between republican traditions and imperial innovation that characterized the early Empire historically might have tilted more decisively toward innovation and autocracy. The religious, cultural, and political landscape of the Empire might have been transformed by decades of Caligulan influence rather than the brief interlude it represented historically. Whether this would have created a more stable and successful empire or accelerated its challenges is one of the most intriguing questions raised by this counterfactual scenario.

Expert Opinions

Dr. Livia Drusilla, Professor of Early Imperial History at Oxford University, suggests:

"Had Caligula ruled for decades rather than years, I believe we would have seen the emergence of a more explicitly autocratic imperial model much earlier than occurred historically. The Augustan compromise—maintaining republican facades while exercising monarchical power—was already strained under Tiberius, and Caligula showed little patience for these pretenses. His reported interest in eastern-style kingship and divine honors suggests he might have transformed the principate into something closer to an oriental monarchy, perhaps resembling what Diocletian would establish centuries later. The Senate would likely have been marginalized more quickly, with power concentrated in the imperial household and exercised through freedmen and equestrian officials rather than the traditional aristocracy. This might actually have created a more efficient administrative system earlier, bypassing some of the tensions that plagued the early Empire. However, it would have represented a more decisive break with Roman republican traditions and might have generated different forms of resistance. The fascinating question is whether such a system would have provided greater stability in the long run or whether it would have exacerbated the tensions between imperial power and aristocratic privilege that periodically destabilized the Empire throughout its history."

Dr. Marcus Aurelius Nepos, specialist in Roman religious history at the University of California, Berkeley, notes:

"Caligula's religious policies, had they been implemented over decades rather than years, might have fundamentally altered the religious landscape of the Empire. His apparent interest in receiving divine honors during his lifetime rather than posthumously could have transformed the imperial cult from the somewhat flexible and locally variable system that developed historically into a more direct and uniform form of emperor worship. This would have created different dynamics for religious minorities, particularly Jews and the emerging Christian movement. His reported plan to place his statue in the Jerusalem Temple might have triggered the Jewish-Roman conflicts decades earlier than historically occurred, potentially altering the development of both Judaism and Christianity in profound ways. The early Christian movement, still in its formative stages during Caligula's reign, might have faced clearer lines of religious conflict earlier, potentially affecting its theological and organizational development. Additionally, Caligula's interest in Egyptian and other eastern cults might have accelerated religious syncretism in the Empire, creating new hybrid religious forms. Rather than the relatively gradual religious evolution that characterized the first century CE historically, we might have seen more dramatic religious transformations and conflicts under a long Caligulan reign."

Dr. Quintus Fabius Maximus, expert in Roman military and provincial administration at the Sorbonne, offers:

"The military and provincial implications of an extended Caligulan reign would have been significant. Caligula's personal connection to the Rhine legions through his childhood might have made the Germanic frontier a particular focus, potentially leading to more aggressive expansion in this region rather than the generally defensive stance adopted historically. Britain might have been incorporated into the Empire decades earlier than under Claudius, allowing for longer Romanization and potentially creating a more thoroughly integrated province. In terms of provincial administration, Caligula showed interest in direct engagement with the provinces, particularly Egypt, which he reportedly considered visiting, and Gaul, where he did travel. This might have led to more direct imperial involvement in provincial affairs, potentially bypassing the traditional senatorial governors in favor of equestrian officials responsible directly to the emperor—a system that developed gradually over centuries historically but might have been implemented more rapidly under Caligula. The question of military loyalty would have been crucial after surviving a Praetorian plot. Caligula might have implemented more extensive loyalty measures within the army's command structure, potentially creating different dynamics between emperor and legions than those that developed historically."