The death of Caesar: do we know the whole story?

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Decimus changed Caesar’s mind. Caesar decided to go to the Senate meeting after all, if only to announce a postponement in person. What he didn’t know was that more than 60 conspirators were waiting for him there, their daggers ready. Decimus, however, was all too aware – he was one of the plots’ ringleaders, and his actions that morning were about to change the course of history.

Despite this, most historians have traditionally cast Brutus and Cassius as the brains behind the conspiracy. In doing so, they’ve followed the lead of Plutarch, who wrote 150 years after the assassination, and Shakespeare, who drew most of his story from Plutarch. They tend to omit Decimus, who Shakespeare misnames ‘Decius’ and mentions only in the scene described above. Yet Decimus was key. His motives are less opaque than most think and his behaviour shows just how well organised the conspirators were.

The earliest surviving, detailed source for Caesar’s assassination makes Decimus the leader of the conspiracy. Sometime within a few decades of the Ides of March, Nicolaus of Damascus, a scholar and bureaucrat, wrote a Life of Caesar Augustus – that is, of Augustus, Rome’s first emperor (reigned 27 BC–AD 14). A later abridgment of this work survives and it focuses on the assassination.

Until recently, scholars have tended to dismiss Nicolaus because he worked for Augustus and so had a motive to attack the conspirators. But recent work suggests that Nicolaus was a brilliant student of human nature who deserves more attention. A series of letters between Decimus and Cicero, all written after the assassination, also shed light on the plot, but they too have been neglected.

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Things turn sour

Unlike Brutus and Cassius, Decimus was Caesar’s man. In the civil war between Caesar and the Roman general Pompey (49–45 BC), Brutus and Cassius both supported Pompey and then later changed sides. By contrast, Decimus backed Caesar from start to finish. During the conflict, Caesar appointed Decimus as his lieutenant to govern Gaul in his absence. At the war’s end in 45 BC, Decimus left Gaul and returned to Italy with Caesar.

Then things turned sour. Between September 45 BC and March 44 BC Decimus changed his mind about Caesar. We don’t know why but it probably had more to do with power than principle. Decimus’s letters to Cicero reveal a polite if terse man of action with a keen sense of honour, a nose for betrayal, and a thirst for vengeance.

Perhaps what moved Decimus was the sight of the two triumphal parades in Rome in autumn 45 BC that Caesar allowed his lieutenants in Spain to celebrate, against all custom. Caesar did not, however, grant a similar privilege to Decimus for his victory over a fierce Gallic tribe.

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Or perhaps it was Caesar’s appointment of his grandnephew Octavian (as Augustus was then known) as his second-in-command in a new war in 44 BC against Parthia (roughly, ancient Iran), Rome’s rival in the eastern Mediterranean. Decimus meanwhile had to stay behind and govern Italian Gaul.

Whatever his motives, once he turned on Caesar, Decimus was indispensable. He was both the plotters’ chief of security and their leading spy. As the only conspirator in Caesar’s inner circle, Decimus was a mole, able to report on what Caesar was thinking. What’s more, Decimus controlled a troupe of gladiators, which played a key role on the Ides.

Caesar remained in Rome between October 45 and March 44 BC – his longest stay there for years. He never revealed a programme but his actions betrayed that he aimed to change Rome’s government. He behaved in ever-more dictatorial ways, summed up in his adoption of the unprecedented title of Dictator for Life.

He maintained Rome’s traditional republican magistracies but elections increasingly became mere formalities – Caesar had the real power of appointment. Consuls, praetors (magistrates) and senators saw power shifting to Caesar’s secretaries and advisors – some of them had only recently become Roman citizens; some were even freedmen (former slaves). Caesar was not a king, but he had acquired the equivalent of royal power.

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There was another issue at play here – the prospect of what would happen after Caesar’s death. To his critics, the favour he showed to Octavian raised the terrifying prospect of a dynasty.

Some Romans responded to Caesar’s growing power with flattery. They voted him a long stream of honours including, most egregiously, naming him a god, with plans afoot for priests and a temple. Others, however, decided that he had to be stopped, and so they decided on assassination. True, they acted in the name of the Republic and liberty and against a budding monarchy but they also saw in his growing influence a threat to their own power and privilege.

Plans to assassinate Caesar are attested as early as the summer of 45 BC but the conspiracy that struck on the Ides of March did not gel until February 44 BC. At least 60 men joined it (of whom we can identify just 20 today – and some of them are little more than names). According to a later writer, Seneca, the majority of the conspirators were not Caesar’s enemies – former allies of Pompey – but his friends and supporters.

That certainly can’t be said for Brutus and Cassius, the best-known conspirators. Cassius was a military man and a former Pompey supporter who despised Caesar’s dictatorial ways. As for Brutus, he was hardly the friend of Caesar whom Shakespeare depicts.

Brutus’s mother was Caesar’s former mistress. However, Brutus supported Pompey until the latter lost to Caesar on the battlefield in 48 BC, at which point Brutus switched sides. He promptly betrayed his ex-chief by providing Caesar intelligence about the likely whereabouts of Pompey, who had escaped after the battle. Afterwards, Caesar rewarded Brutus with high office.

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This, however, was to prove the high point of Caesar and Brutus’s relationship. In the summer of 45 BC, Brutus divorced his wife and remarried. His new bride was Porcia, his cousin and, far more pertinently to this story, daughter of Caesar’s late archenemy Cato.

Crucially, in the winter of 44 BC, Caesar’s opponents began calling on Brutus to uphold the tradition of his ancestors, who included the founder of the Roman Republic, Lucius Junius Brutus, the man who had led the expulsion of Rome’s kings hundreds of years earlier. And so, through a combination of pride, principle – and, perhaps, love for his wife – Brutus turned on Caesar.

Military precision

The plot to assassinate Caesar succeeded because it was meticulously planned, and flawlessly executed. With generals such as Decimus, Cassius and Caesar’s veteran commander Trebonius involved, one would expect nothing less than military precision. The assassins chose to end Caesar’s life themselves rather than by hiring killers – a decision that showed their seriousness of purpose. And by striking at a Senate meeting they made it a public act rather than a private vendetta – an assassination and not a murder.

That this was a professional operation is even reflected in the killers’ choice of weapon. Caesar’s assassins attacked him with daggers and not, as is sometimes imagined, with swords. The latter were too big to sneak into the Senate House and too unwieldy for use in close quarters. In particular, the killers used a military dagger (the pugio), which was becoming standard issue for legionaries.

Military daggers were not only practical weapons but also honourable ones. Caesar’s supporters later called the assassins common criminals and accused them of using sicae, a short, curved blade that had the negative connotation of a switchblade or flick knife. So, in 44 BC, Brutus issued a coin that celebrated the Ides of March with two military daggers. Again, he wanted to show that the assassins were no mere murderers.

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The Roman Senate House still stands in the Roman Forum and most visitors assume that Caesar was killed there – but he was not, nor on the Capitoline Hill, as Shakespeare states. The assassination took place about half a mile away from the Forum in Pompey’s Senate House, ironically built by Caesar’s great rival. It was part of a huge complex including a theatre, a park, a covered portico, and shops and offices. Gladiatorial games took place in the theatre on the Ides of March, which gave Decimus an excuse for deploying his gladiators near Pompey’s Senate House. Their real purpose was as a backup security force.

As a general, Caesar had a bodyguard but he made a point of dismissing it after returning to civilian life in Rome. He wanted to seem accessible and fearless. What’s more, only senators could enter a Senate meeting, so most of Caesar’s retinue would have had to remain outside the building. This made the dictator uniquely vulnerable inside the Senate House. Still, Caesar had appointed many of the senators personally, and they included military men. If they came to Caesar’s aid, they could overwhelm the assassins.

The assassins’ response to this threat was to attack at speed, isolating their target before striking. Even before Caesar took his seat on the tribunal, several assassins stood behind the chair while others surrounded him as if trying to grab his attention. The truth is that they were forming a perimeter.

Then the attack sprang into action. Tillius Cimber, a hard-drinking scrapper of a soldier whom Caesar favoured, held his hands out disrespectfully and pulled at Caesar’s toga. At this signal, his co-conspirators struck, led by Publius Servilius Casca.

What were Julius Caesar's last words?

Caesar immediately called out to Cimber, “Why, this is violence”, and hurled an oath at Casca, labelling him either “impious” or “accursed”. However, he never said: “Et tu, Brute?” (“You too, Brutus?”) – that phrase is a Renaissance invention. Ancient authors report a rumour that Caesar said to Brutus, in Greek: “You too, child.” But they doubt that he even said that.

Caesar, the old warrior, tried to fight back. He stabbed Casca with his stylus – a small, pointed, iron writing utensil – and managed to get back up. Two of his supporters among the senators, Lucius Marcius Censorinus and Gaius Calvisius Sabinus, then attempted to reach him but the conspirators blocked their way, and forced them to flee.

Meanwhile, Trebonius had been assigned to buttonhole his old comrade Mark Antony and engage him in conversation outside the Senate’s door. Antony was a veteran soldier, strong, dangerous and loyal to Caesar. If he’d entered the Senate room, he would have sat on the tribunal with Caesar and could have come to his aid.

With Mark Antony detained by Trebonius, there was little Caesar could do to defend himself. It probably took only minutes for him to die – succumbing to what most of the sources state were 23 wounds. Before the end, he wrapped his toga around his face and, in an ironic turn of events, fell at the foot of a statue of his rival, Pompey.

For all its brilliance, the plot to kill Caesar didn’t prove the panacea that the assassins hoped. Civil war soon broke out again and, to a man, they were to suffer violent deaths. What’s more, the Republic that they aimed to defend perished and gave way to an empire. That, however, does not brand them as foolish idealists. It merely shows that their political acumen did not match the military skill they displayed on the Ides of March.

Barry Strauss (@barrystrauss) is a professor of history and classics at Cornell University. His latest book, The Death of Caesar: The Story of History’s Most Famous Assassination, is published by Simon & Schuster this month.

This article was first published in the March 2015 issue of BBC History Magazine