When Caligula became emperor, he performed an act that no Roman leader had ever done before. He placed the faces of his sisters on official currency and inserted their names into sacred oaths, granting them more structural power than any other women in the history of Rome. Yet, what he did with those same sisters behind closed doors was something the ancient world could barely describe with words. This is the history of Caligula and his three sisters, and it is far darker than history typically admits. But before entering the palace where these three sisters lived and suffered, let us examine what power did to this family, what it deformed, and what it destroyed.
The boy who would one day be known as Caligula was born into the most beloved family in Rome. His father, Germanicus, was the golden general of the empire, adored by both soldiers and citizens. His mother, Agrippina the Elder, was the granddaughter of Augustus himself. They had nine children, six of whom survived infancy: three boys and three girls. They were the perfect Roman family, the hope of an entire empire. And then Rome destroyed every single one of them.
It all began with Germanicus. He was poisoned in Syria in the year 19 AD, most likely by orders of Emperor Tiberius, who feared the immense popularity of his nephew. The golden general died at just 33 years old, and Rome wept. But Tiberius did not weep. Tiberius watched, and then he turned his attention toward the remaining family. Agrippina the Elder, Caligula’s mother, spoke too much. She was too popular and represented a painful reminder that Rome loved Germanicus more than its own emperor. Tiberius ordered her arrest and exiled her to the island of Pandataria. There, alone, she was slowly condemned to starvation. Some sources claim she attempted to resist, refusing to eat by her own choice, and that the guards intervened to keep her alive only to prolong her suffering. She died in the year 33 AD.
Caligula’s eldest brother, Nero Caesar, was arrested under false accusations and sent into exile, where he was killed or driven to suicide. His second brother, Drusus Caesar, was locked away in the dungeons beneath the imperial palace. He died slowly of starvation, driven to despair. Ancient sources relate that near the end, hunger consumed him so completely that he attempted to eat the stuffing of his own mattress. He died in the year 33 AD, the same year as his mother. Three members of the family were dead in just a few years, all destroyed by the emperor who was supposed to protect them.
Caligula survived not because Tiberius cherished him, but because he considered him useful. The old emperor summoned the teenager to his villa on Capri, that infamous island refuge where Tiberius spent his final years surrounded by cruelty and excess. Suetonius described the island as a place of calculated degradation, where the emperor played sadistic games with his guests and brutally punished any sign of disloyalty. That was where Caligula grew up. That was the place that molded him, not philosophy, not military strategy, nor the virtues that Rome claimed to venerate. He learned vigilance, manipulation, and the absolute certainty that anyone who showed what they truly felt would be destroyed by it.
Through all of that, through the deaths, the exile, and that island of horrors, three people remained. Three sisters survived the exact same nightmare: Agrippina the Younger, Julia Drusilla, and Julia Livilla. They were everything he had left, the only family that had not been torn away from him, the only people who understood what it meant to watch your parents and brothers be systematically erased. What Caligula did next with his sisters, whether called love, obsession, or something far more disturbing, was born from that bond, the shared trauma of being the last ones left standing.
In March of the year 37 AD, Tiberius died. Some say it was from natural causes, while others assert that Caligula may have accelerated his end when he saw that the old man was taking too long to die. Whichever the case, the boy from Capri suddenly became the emperor of Rome. He was barely 24 years old, and his first act tells you absolutely everything about what truly mattered to him. He brought his sisters back home.
He brought them back to Rome with honors that no Roman woman had ever received before. He granted all three of them the privileges of the Vestal Virgins, the most sacred women in Rome, including the right to witness the public games from the best seats in the stadium. He also included their names in the oath of loyalty that every Roman citizen, soldier, and senator was required to pronounce. The oath read:
“I will consider my own life and that of my children no more valuable than that of Caligula and his sisters.”
Every person in the empire was swearing allegiance not only to the emperor, but also to his sisters by their proper names: Agrippina the Younger, Julia Drusilla, and Julia Livilla. Three women were mentioned in the same breath as the emperor himself. Then, he placed their faces on Roman coins. On one side was the profile of Caligula, and on the other side were his three sisters, represented as goddesses of security, harmony, and fortune. They were the first coins in the entire history of Rome to display living women by name. The message was clear: these women were not just family, they were part of the state, part of the empire, part of him.
But there was one sister who received something more, something that went far beyond political honor and entered a territory that made Romans deeply uncomfortable. Julia Drusilla was born just one year after Caligula. They grew up together, survived together, lost everything together, and when Caligula became emperor, he did not just honor her alongside his sisters; he separated her, elevated her, and treated her differently from any other person in his life. He married Julia Drusilla to his close friend Lucius Cassius Longinus, a former consul, which was a respectable marriage and a normal political alliance by Roman standards.
And afterward, he took her back. Not in secret, not gradually; he simply removed Julia Drusilla from her husband’s house and installed her in the imperial palace. According to Suetonius, he treated her as if she were his legitimate wife. He sat at her side during banquets, in the place reserved for an empress. She lived with him, appeared alongside him, and occupied a status that no sister should occupy in Roman society. Rome whispered, but Caligula did not care about the whispers. He married Julia Drusilla off again, this time to Marcus Aemilius Lepidus, his closest friend and political ally. In appearance, it seemed like a strategic move. Marcus Aemilius Lepidus had powerful connections and was a descendant of Augustus, making him an excellent match for the favorite sister of the emperor.
Yet, inside the palace, nothing changed. Julia Drusilla continued living with Caligula, continued sitting at his side at every state dinner, and continued occupying the place that belonged to an empress, not a sister. Marcus Aemilius Lepidus had a wife in name only; Caligula had her in everything else. Imagine being Marcus Aemilius Lepidus, married to the most powerful woman in Rome, and yet your wife lives in her brother’s palace, appears by her brother’s side, and acts as her brother’s companion before the eyes of everyone. You are the husband, but you are not the man to whom she belongs. Everyone in the court knows it, all of Rome knows it, and nobody says a single word because the man at the center of it all is the emperor, and emperors do not share what they consider theirs.
Now imagine being Julia Drusilla, caught between a husband and a brother, between what Roman society expected and what was demanded by the most powerful man in the world. Did she choose it? Did she desire it? Did she have any real choice? When the emperor tears you from your husband and installs you in his palace, the word no ceases to exist, not for a sister, not for anyone.
This is where the obsession became deeper. In October of the year 37 AD, just seven months after beginning his reign, Caligula fell gravely ill. Some modern historians believe it may have been epilepsy, while others suggest a nervous breakdown, the accumulated trauma of a lifetime of losses finally breaking through the surface. Whatever it was, Rome believed he was dying. Sacrifices were offered, citizens prayed in the streets, and the entire empire held its breath. Caligula, believing he was on his deathbed, made a decision that shocked every senator, every advisor, and every Roman who heard it. He named Julia Drusilla his heir. Not a general, not a senator, not a male cousin, nor an adopted son, but his sister, a woman in an empire that had never allowed a woman to rule, that had never even considered the possibility. Caligula drafted his will and left her everything: his properties, his power, all of Rome. No Roman emperor had ever done anything like that before, and no Roman emperor would ever do it again.
Think about what that means. In the moment when everything disappears, when death is before you and every mask falls, the person Caligula trusted to hand over the entire world was not a politician, not a commander, nor even a man. It was his sister.
Caligula survived, but something changed. That illness marked a point of no return in practically all ancient accounts of his reign. Before falling ill, he is described as generous, popular, and even promising. Afterward began the cruelty, the executions, the paranoia, and the divine delusions. The Caligula that history remembers, the monster, was born in that sickbed. But there was one thing that did not change: his focus on Julia Drusilla. If anything changed, it was that it became even more intense. After looking death in the eye and returning, Caligula’s control over her became still stronger. She continued to be at the center of everything, his anchor, his only constant, the single fixed point in a mind that was rapidly losing its grip on everything else.
It is here, with Julia Drusilla living in his palace, sitting by his side, named as his heir, and treated in every way as his companion and not his sister, that the ancient sources make their darkest accusations. Suetonius wrote that Caligula maintained unusually close and inappropriate relations with his sisters, and that Julia Drusilla was his favorite above the others. He even claims that their grandmother, Antonia the Younger, caught them together when they were young. He also describes a ritual at imperial banquets where Caligula would seat each of his sisters in turn in the place next to him, the couch situated below the host, a place that Roman tradition reserved exclusively for a man’s wife. His actual wife rested above him, while his sister occupied that same position.
Now, whether these accounts describe literally what occurred within the walls of the palace or if they were simply the darkest interpretation of a bond so intense that the Romans could only explain it through their greatest taboo, there is something impossible to deny. The relationship between Caligula and Julia Drusilla was something Rome had never seen. It broke all boundaries between emperor and family, between brother and sister, between political power and personal obsession. The Romans did not have a category to explain what they were witnessing, so they resorted to the most disturbing one they knew.
And then Julia Drusilla died, and everything that remained of Caligula’s sanity died with her. On June 10 of the year 38 AD, Julia Drusilla disappeared forever. She was barely 21 years old. The most probable cause was an epidemic that was sweeping through Rome at that time, a fever, an illness, the kind of death that simply happens and that no imperial power can prevent.
Caligula collapsed. What happened next was so extreme that even by Roman standards, it looked like an absolute psychological breakdown. He declared a period of public mourning, but not a normal mourning of dark clothing and canceled parties for a few weeks. He made it a capital offense to laugh. He made it a capital offense to bathe. He made it a capital offense to dine with your parents, with your wife, or with your children. If you smiled during the mourning period for Julia Drusilla, you could be executed. If you washed your body, you could be executed. If you dined with your own family, you could be executed. Rome fell silent, an entire city, an entire empire paralyzed by the grief of a single man and by the absolute power he had to impose it.
But Caligula did not remain in Rome to mourn her. He could not do it. The palace, the city, every room where Julia Drusilla had existed became unbearable. So he fled in the middle of the night without prior warning. He escaped from Rome, crossed through Campania in a frenzy, took a boat toward Syracuse, and then returned as suddenly as he had left. He did not shave, he did not cut his hair, and he wandered like a ghost, carrying his grief upon his body for everyone to see.
Then he did something unprecedented. He went to the Senate and demanded that Julia Drusilla be converted into a goddess. Not simply honored, not simply remembered, but a divine, immortal goddess equal to Venus, equal to Minerva, equal to the gods themselves. The Senate was terrified. Julia Drusilla became Diva Drusilla Panthea. Panthea means the universal goddess. She received her own temple, her own priesthood, and her own sacred games. They even placed a cult statue of her in the temple of Venus. A senator, desperate to win the favor of Caligula, went so far as to swear under oath that he saw the soul of Julia Drusilla ascending to heaven, rising from the funeral pyre to take her place among the gods. Caligula rewarded him enormously. Whether that senator believed his own story or not was irrelevant. The important thing was this: the emperor needed his sister to be something more than a dead woman; he needed her to be eternal.
After all of that, after the mourning laws, the nightly flight, and her deification, Suetonius records one last detail. Caligula never again swore upon any important matter, whether before the Senate, before the people, or before the gods, without invoking the name of Julia Drusilla. She was dead, but he refused to let her go. That refusal, that absolute inability to survive the absence of his sister, was what transformed Caligula from a disturbed emperor into the monster that history remembers. The cruelty that came afterward was the cruelty of a man who had lost the only thing that kept him whole.
Caligula still had two living sisters. Agrippina the Younger and Julia Livilla remained alive, remained at court, and continued carrying the honors that he himself had given them. You might think that losing Julia Drusilla would make him cling even tighter to them. You might think that grief would lead him to protect the last remaining pieces of his family. You would be wrong, because what Caligula did with Agrippina the Younger and Julia Livilla after the death of Julia Drusilla was not love; it was punishment. It was rage, the fury of a broken man who looked at his surviving sisters and saw two women who continued breathing while the only one who truly mattered to him was no longer there. What occurred next included a conspiracy, a betrayal, three daggers, and a humiliation so public that it resonated in the history of Rome for centuries.
After the death of Julia Drusilla, something fundamental broke in Caligula’s relationship with his surviving sisters. The brother who once placed their faces on coins and their names in sacred oaths now looked at Agrippina the Younger and Julia Livilla with something colder than love, something much closer to contempt. According to Suetonius, Caligula began to involve his two remaining sisters in deeply inappropriate arrangements with his own favorites. He linked them closely with the men of his most intimate circle, companions, allies, men whom he kept close. Whether this occurred exactly this way or was a later exaggeration to feed his legend of depravity, the accusation reveals something crucial: the extent to which that relationship had collapsed. These were the same women whom he had elevated above any other woman in Rome, the same sisters whose names were pronounced alongside his own in oaths of loyalty, and now, according to ancient sources, they were utilized as political tools, exchanged as favors, and reduced from goddesses engraved on coins to pieces moved between powerful men.
But Agrippina the Younger and Julia Livilla were not passive victims. They were daughters of Germanicus, granddaughters of Agrippina the Elder, the woman who defied Tiberius until it cost her her life. They had survived the same nightmare childhood as Caligula, watched the destruction of the same parents and the same brothers, and they learned the same lesson that he did: when you are trapped in a palace with a monster, you either submit or you fight. They chose to fight.
The conspiracy began around the year 39 AD, approximately one year after the death of Julia Drusilla. Agrippina the Younger and Julia Livilla formed an alliance with Marcus Aemilius Lepidus, the man who had been the husband of Julia Drusilla, the man whom Caligula had personally chosen as his closest friend, the man who, after the death of Julia Drusilla, was seen by many as the most likely successor to the throne. But Marcus Aemilius Lepidus was not just their political ally. According to ancient sources, he was also the lover of both of them at the same time. Agrippina the Younger and Julia Livilla maintained relations with the widower of their dead sister while planning to use him to overthrow their own brother.
Think of the layers of betrayal that existed here. Marcus Aemilius Lepidus, the man in whom Caligula trusted more than anyone, was sleeping with his two surviving sisters. Those sisters, the women Caligula had elevated almost to a divine level, were conspiring to murder him. And the man chosen to replace him on the throne was the widower of Julia Drusilla, the sister Caligula loved with an obsession so extreme that he turned her into a goddess. Everything Caligula loved was turning against him. Every bond he believed he had was a lie. Every person he trusted was planning his death.
History remembers this conspiracy as the plot of the three daggers, and for a time, it might have worked. But Caligula, despite all his madness, remained the boy who survived the unpredictable cruelty of Tiberius. He remained the boy who learned to observe, to listen, and to trust no one. In the autumn of the year 39 AD, while he was in Upper Germania with his legions, he discovered the plot. The evidence was devastating: handwritten letters, plans, details about how they thought to kill him, names, dates, and methods. It was the type of evidence that leaves no room to deny anything. Marcus Aemilius Lepidus was executed immediately without trial, a quick death for the man who was married to one sister while sleeping with the other two and planning to steal the throne.
But for Agrippina the Younger and Julia Livilla, Caligula designed something worse than death, something that would humiliate them in a way that Rome would never forget. He forced Agrippina the Younger to carry the ashes of Marcus Aemilius Lepidus back to Rome on foot, inside a box, through the streets. It was a public march of shame, the emperor’s own sister carrying the remains of her dead lover while soldiers watched and crowds stared, and the entire empire understood what happens when you betray Caligula. Imagine being Agrippina the Younger, walking kilometer after kilometer with the ashes of the man you loved, of the man with whom you conspired, of the man who was supposed to save you from your brother. Every step was a punishment, every kilometer was a message, and at the end of the road, there was no mercy waiting for her.
Caligula sent both sisters to the Pontine Islands into exile. It was the same remote, barren exile capable of destroying the soul that had killed their mother, the same punishment that Tiberius had used against his family a generation before. The cycle repeated itself; the children suffered the same fate as their parents. When Caligula announced their banishment, he made one thing absolutely clear. He told the Senate:
“I do not only have islands, I also have swords.”
The message was simple: be grateful that I am exiling them, because the alternative was what happened to Marcus Aemilius Lepidus.
In the Pontine Islands, Agrippina the Younger and Julia Livilla were separated, each sent to a different island, each completely alone. They were left without servants, without comforts, and without communication between themselves or with Rome, experiencing only isolation, silence, and the slow understanding that their brother had won and they had lost everything.
Meanwhile, in Rome, Caligula continued to fall apart. His cruelty accelerated. He forced senators to run alongside his chariot wearing their robes, humiliated guests at his banquets, threatened them, and at times punished them brutally. He even opened an establishment within the imperial palace itself, forcing noble women and free-born youths to perform degrading roles while he kept the profits. He declared himself a living god, raised temples in his honor, dressed as various deities, and according to accounts, maintained conversations with Jupiter as if they were equals. He named his daughter Julia Drusilla in honor of the dead sister whom he could never let go. He took the child to every temple of every goddess in Rome, one by one, and finally placed her upon the lap of a statue of Minerva, begging the goddess to raise and educate the child, as if a stone goddess could replace the real woman he lost.
During all that time, the executions continued. Anyone who looked at him wrong, anyone who did not applaud his shows with enough enthusiasm, or anyone who accidentally reminded him of the family he destroyed and the sister he lost fell victim. Rome endured this for two more years, two years of increasing madness, increasing cruelty, and ever greater divine delusions.
Then, on January 24 of the year 41 AD, the Praetorian Guard decided that they had had enough. The assassination occurred in a narrow passageway beneath the palace. Cassius Chaerea struck first, and the other conspirators followed him. Caligula was attacked and killed by the very men who were supposed to protect him. But the slaughter did not end with the emperor. His wife, Caesonia, was found and killed. Then the soldiers found his daughter, Julia Drusilla, the baby he named in honor of his adored sister, the girl he carried to all the temples of Rome. She was barely two years old. They killed her. The last Julia Drusilla died just like the first: young, violently, before having the opportunity to become anything more than the symbol of her father’s broken love.
Now the history turns toward the two sisters who survived. The fate of Julia Livilla came first. When their uncle Claudio became emperor following the assassination of Caligula, he ordered both sisters to be brought back from exile. For a brief moment, it looked like mercy, as if the cycle of punishment could finally end. But Claudio had a wife, Messalina. Messalina looked at Julia Livilla and saw a threat: a beautiful, popular princess with imperial blood and potential influence that could challenge her own. Messalina convinced Claudio that Julia Livilla was guilty of adultery with Seneca. The charges were almost certainly false, but Claudio, controlled by his wife, sent her back into exile. This time, there would be no return. At the end of the year 41 or the beginning of 42 AD, Claudio ordered the execution of Julia Livilla. The method was starvation, exactly like her mother, the same slow, agonizing disappearance that Agrippina the Elder suffered a decade before. Julia Livilla was only 24 years old. She died alone, hungry, and forgotten on an island that history barely remembers. The daughter of Germanicus, the sister of an emperor, the woman whose face appeared on Roman coins as a goddess of fortune, died of hunger in exile, and nobody arrived to save her.
And then there was Agrippina the Younger, the eldest sister, the woman who carried the ashes of Marcus Aemilius Lepidus through the streets, the woman who conspired against her brother and paid for it with years of isolation. Agrippina the Younger survived because Agrippina the Younger always survived, and that is exactly what made her the most dangerous of the three. When Claudio brought her back from exile, she did not retire in silence; she did not hide from power. She walked directly back to the palace and began the patient, calculated work of becoming indispensable. She waited for Messalina to self-destruct, and Messalina did so in spectacular fashion. When Claudio was left alone and vulnerable, Agrippina the Younger made her move. She married him, her own uncle. The Senate was horrified, and the people called it obscene, but Agrippina the Younger did not care what they called it; she only cared about one thing: putting her son on the throne. Her son was named Nero. You know him as Nero.
Agrippina the Younger poisoned Claudio with mushrooms, placed Nero on the throne, and remained behind him, whispering orders, pulling strings, and controlling every breath he took. It was the same pattern that her brother Caligula had with Julia Drusilla, but inverted. Now it was the sister who controlled; now it was the sister who refused to let go of power. And Nero, just like Caligula before him, ended up deciding that the person who controlled him had to disappear. The poison failed, the boat that was supposed to sink failed, and it ended with soldiers with swords and the last words of Agrippina the Younger demanding that they strike the womb that had brought him into the world. The last surviving sister of Caligula died at the hands of her own son, murdered by the emperor she herself created, just as Caligula probably would have killed her if exile had not arrived first.
Three sisters, three destinies. Julia Drusilla, the favorite, the obsession, the sister Caligula loved so absolutely that he attempted to turn her into a goddess when he could not keep her alive, dead at 21 years old from a fever that no imperial power could stop. Julia Livilla, the forgotten, exiled by her brother, condemned to die of hunger by the wife of her uncle, dead at 24 years old, repeating exactly the destiny of her mother on a prison island that history barely remembers, her name erased from monuments, her story reduced to a footnote. Agrippina the Younger, the survivor, the one who survived her brother, fooled her uncle, and built an empire for her son, dead at 43 years old, stabbed by soldiers sent by her own son in a villa by the sea, her last act to curse the son she created, just as Caligula’s last act was to deify the sister he lost.
And Caligula, the boy who watched his mother be dragged away in chains, the teenager who learned cruelty on the island of Tiberius, the emperor who placed the faces of his sisters on coins and their names in sacred oaths, the brother who loved one sister too much, completely destroyed the other two and left a trail of destruction so deep that it resonated through three generations of Roman emperors. The family of Germanicus was supposed to be the hope of Rome, nine children born among privileges and promises, and in the end, every single one of them was dead: dead of hunger, exiled, murdered, executed, stabbed. Not a single one died in peace. Three sisters entered the palace of Caligula; one became a goddess, one became a ghost, and one became a monster in her own right. And the brother who claimed to love them all left nothing behind except a name that for 2,000 years has been synonymous with madness.
