Caligula, Roman Emperor 37-41 CE: Life, Reign, Legends and Death
Caligula, the Roman emperor from 37 to 41 CE: his family and childhood, his popular first months, his illness, the famous stories about his cruelty and what the evidence supports, and his assassination.
Last updated September 2026
Contents15
- Caligula at a glance
- Childhood and the nickname "little boot"
- Caligula's family
- Timeline of Caligula's life
- How Caligula became emperor
- The illness of 37 CE
- Caligula as Roman emperor, 37-41 CE
- Caligula and the Senate
- Caligula and the provinces
- Stories about Caligula: what the evidence supports
- What coins and inscriptions show
- The assassination, 24 January 41
- The sources on Caligula
- Caligula in later culture
- Verdict: Caligula as Roman emperor
Caligula was the third Roman emperor and one of the most notorious. He came to the throne in 37 CE, aged 24, to great public joy. His own guards murdered him less than four years later.
Almost all we know about him comes from writers who hated him. This page sets out the facts of his life and reign. Then it separates the well-supported events from the famous stories that historians doubt.
TL;DR: Caligula was born in 12 CE and was emperor from 37 to 41. He was the son of the popular general Germanicus and a great-grandson of Augustus. His first months were popular. After a serious illness in late 37, his rule turned harsh and costly. The Praetorian Guard killed him on 24 January 41. Stories that he made his horse a consul, or went mad, come from hostile sources and are disputed.
Caligula at a glance
| Field | Record | Status |
|---|---|---|
| Full name | Gaius Julius Caesar Germanicus | Reviewed |
| Born | 31 August 12 CE, Antium (Anzio), Italy | Reviewed |
| Parents | Germanicus and Agrippina the Elder, a granddaughter of Augustus | Reviewed |
| Became emperor | March 37 CE, after the death of Tiberius on 16 March | Reviewed |
| Died | 24 January 41 CE, Rome, assassinated | Reviewed |
| Wives | Junia Claudilla, Livia Orestilla, Lollia Paulina, Milonia Caesonia | Reviewed |
| Child | A daughter, Julia Drusilla, killed with him | Reviewed |
| Dynasty | Julio-Claudian | Reviewed |
| Succeeded by | His uncle, Claudius | Reviewed |
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Childhood and the nickname "little boot"
Gaius was the youngest son of Germanicus. Germanicus was the adopted son of Tiberius and one of the most popular men in Rome. As a small child, Gaius went with his parents to the army on the Rhine.
His mother dressed him in a tiny soldier's uniform. The troops called him Caligula, "little boot", after the army sandal, the caliga. He disliked the name as an adult.
His father died in Syria in 19 CE. Many Romans at the time believed he was poisoned. In the 20s and early 30s, Sejanus, the head of the Guard, grew very powerful.
Gaius's mother and his two elder brothers were arrested. All three died in custody or exile. Gaius survived by keeping quiet. From 31 CE he lived with the aged Tiberius on the island of Capri.
Caligula's family
Caligula was a Julio-Claudian on both sides. His mother linked him to Augustus. His father linked him to Tiberius.
| Relative | Relation to Caligula |
|---|---|
| Augustus | Great-grandfather, through his mother |
| Tiberius | Great-uncle and adoptive grandfather |
| Germanicus | Father, adopted son of Tiberius |
| Agrippina the Elder | Mother, granddaughter of Augustus |
| Nero Caesar and Drusus Caesar | Elder brothers, both died after arrest |
| Agrippina the Younger, Drusilla, Livilla | Sisters |
| Claudius | Uncle, his successor |
| Nero (emperor 54-68) | Nephew, son of Agrippina the Younger |
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Being a descendant of Augustus mattered. It gave Caligula a claim that the army and the people accepted. That was true even though he had no experience of government.
Timeline of Caligula's life
| Year (CE) | Event |
|---|---|
| 12 | Born at Antium on 31 August |
| 14-16 | Lives in the army camps on the Rhine with his parents |
| 19 | His father, Germanicus, dies in Syria |
| 29 | His mother and eldest brother are exiled |
| 31 | Joins Tiberius on Capri |
| 33 | Holds the office of quaestor, his only major post before becoming emperor |
| 37 | Becomes emperor in March; falls ill in October |
| 41 | Killed on 24 January, aged 28 |
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How Caligula became emperor
Tiberius died on 16 March 37. His will named Gaius and Tiberius's own grandson, Tiberius Gemellus, as joint heirs. The Senate, backed by Macro, head of the Guard, set the will aside. It gave Gaius sole power. He was 24 and had held almost no public office.
The start of his reign was met with joy. He called exiles home and stopped treason trials for a time. He paid out Tiberius's gifts to the people and the army, and he put on lavish games. He adopted Gemellus as his son. Roman writers say that thanks were offered across the empire in the first three months of his rule.
The illness of 37 CE
In October 37 Caligula fell seriously ill. The Jewish writer Philo of Alexandria met him in person. He wrote that the whole empire waited for news. Caligula recovered. But ancient writers date the change in his rule from this point.
Soon after, he had Gemellus killed. He forced Macro and his own father-in-law to take their own lives. Treason trials came back. What the illness was is unknown. So is whether it changed his mind, or only his behaviour.
Caligula as Roman emperor, 37-41 CE
Caligula's reign was short, but several of its projects can be traced in the evidence.
| Year | Event |
|---|---|
| 37 | Accession; popular measures; illness in October |
| 38 | Death of his sister Drusilla, whom he had declared a goddess |
| 38 | Work begins on two new aqueducts, later finished by Claudius |
| 39 | Bridge of boats across the Bay of Naples at Baiae; march to Germany |
| 40 | Aborted invasion of Britain; King Ptolemy of Mauretania killed |
| 40 | Orders a statue of himself set up in the Temple in Jerusalem; the order is delayed and dropped |
| 41 | Assassinated on 24 January |
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He also brought from Egypt the obelisk that now stands in St Peter's Square in Rome. It was meant for a circus in the Vatican area. He spent heavily on games, buildings and his court. That drained the treasury that Tiberius had left full, and new taxes followed.
Caligula and the Senate
Caligula's worst relations were with the Senate. Early in his reign he promised to share power. He gave back some of the Senate's roles. After 39 he turned against it. He accused senators of plotting against him and brought back treason trials.
The ancient writers describe him shaming senior senators in public. Whatever the details, by 41 many senators had reason to fear him. Some knew of the plot that killed him.
Caligula and the provinces
Caligula made important changes in the east. In 37 he gave his friend Herod Agrippa, grandson of Herod the Great, a kingdom in the north of Judaea. It was later enlarged. In Alexandria, violence broke out between Greek and Jewish residents in 38.
Both sides sent envoys to Rome. Philo led the Jewish group in 40. In North Africa, Caligula called King Ptolemy of Mauretania to Rome and had him killed. Under Claudius, the kingdom then became a Roman province.
Stories about Caligula: what the evidence supports
The famous stories
Caligula's madness, his horse and other stories.
Status: Disputed Told by hostile ancient writers. Doubted by many modern historians.
Note: Suetonius and Cassius Dio say Caligula planned or promised to make his horse Incitatus a consul. They do not say he did it. They also say he claimed to be a god and slept with his sisters. And they say he had soldiers gather seashells on the Channel coast as "spoils of the ocean".
These writers lived generations later. They drew on sources hostile to him. Modern historians accept that he was a harsh, often cruel ruler. But many read the stories as exaggeration, political insult or jokes taken the wrong way. They reject any firm diagnosis of madness.
Sources: Britannica, "Caligula"; De Imperatoribus Romanis, "Gaius (Caligula)".
What coins and inscriptions show
Coins give evidence that does not depend on later writers. Early in his reign, Caligula issued a bronze coin showing his three sisters, Agrippina, Drusilla and Julia Livilla. They appear as figures of Roman virtues.
It was unusual to honour living women this way. Other coins honour his parents and his brothers, and stress his descent from Augustus and Germanicus. These official images show how he wanted to be seen. He wanted to look like the heir of a beloved family, not a tyrant.
The assassination, 24 January 41
By 41 Caligula had offended the Senate, the palace staff and officers of his own guard. Cassius Chaerea, an officer of the Guard whom Caligula often mocked, led the plot. On 24 January, during games on the Palatine Hill, the plotters stabbed him in a covered passage of the palace. They also killed his wife, Milonia Caesonia, and his baby daughter.
The Senate briefly debated bringing back the republic. Meanwhile, soldiers searching the palace found Caligula's uncle Claudius. They took him to their camp, and the Guard hailed him as emperor. His reign is covered on the Claudius page.
The sources on Caligula
Our picture of Caligula depends on a small number of writers.
| Writer | When | What they offer |
|---|---|---|
| Philo of Alexandria | Contemporary; met Caligula in 40 | An eyewitness account of a Jewish embassy, hostile to the emperor |
| Seneca the Younger | Contemporary | Brief, bitter remarks; Seneca had personal reasons to dislike him |
| Josephus | Late 1st century | A detailed account of the assassination |
| Suetonius | Early 2nd century | A full biography mixing facts, rumour and anecdote |
| Cassius Dio | Early 3rd century | A year-by-year narrative |
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The books of Tacitus's Annals that covered Caligula's reign are lost. That gap is one reason the lurid stories of Suetonius dominate the popular image.
Caligula in later culture
Caligula's name as the mad emperor has made him a favourite subject for writers and filmmakers. Albert Camus wrote the play Caligula, first staged in 1945. Robert Graves wrote the novels I, Claudius and Claudius the God. They, and the 1976 BBC series based on them, drew a vivid portrait from Suetonius. These works shape the popular image far more than the thin evidence does.
Suetonius wrote a life of Caligula in The Twelve Caesars, our pick for the best ancient source. It is one of seven in our guide to the best Roman history books.
Verdict: Caligula as Roman emperor
Caligula ruled for less than four years, from March 37 to January 41 CE. He began as a hugely popular young emperor. He ended murdered by his own guards, after he had turned the Senate and the court against him.
The facts of his reign are secure. The stories of madness, incest and a consul horse are not, so this page marks them as disputed. For the emperors before and after him, see Tiberius and Claudius. For every emperor, see emperors of Rome.
The wider story, from Augustus to 1453, is on the Eastern Roman Empire page.
Sources checked for this page
- Britannica, "Caligula"
- De Imperatoribus Romanis, "Gaius (Caligula)"
- World History Encyclopedia, "Caligula"
- Suetonius, "The Life of Caligula", in the LacusCurtius edition (University of Chicago)
- BBC History, "Caligula"
Questions people also ask
Why was Caligula called Caligula?
Caligula means 'little boot'. As a small child he lived in his father's army camps on the Rhine, dressed in a miniature soldier's uniform with military boots, called caligae, and the soldiers gave him the nickname.
Did Caligula make his horse a consul?
No ancient source says he did. Suetonius and Cassius Dio say he planned or promised to make his favourite horse, Incitatus, a consul. Many historians read the story as a joke or an insult to the Senate, if it happened at all.
How did Caligula die?
He was stabbed to death on 24 January 41 CE in a passage of the palace on the Palatine Hill, by officers of the Praetorian Guard led by Cassius Chaerea. His wife and young daughter were killed too.
Who succeeded Caligula?
His uncle Claudius, whom the Praetorian Guard proclaimed emperor on the day after the murder.
How old was Caligula when he died?
He was 28. He was born on 31 August 12 CE and killed on 24 January 41 CE, after a reign of just under four years.
Was Caligula really insane?
There is no reliable way to know. Ancient writers describe erratic and cruel behaviour, but they were hostile to him and wrote long after his death. Modern historians disagree about how much to believe, and none can offer a medical diagnosis.
What did Caligula build?
He began two aqueducts in 38 CE, the Aqua Claudia and the Anio Novus, which Claudius completed. He also brought the obelisk that now stands in St Peter's Square from Egypt, and built a bridge of boats across the Bay of Naples at Baiae.
What was Caligula's real name?
Gaius Julius Caesar Germanicus. Caligula, meaning 'little boot', was a childhood nickname from the army camps, and Romans of his time usually called him Gaius.