The Ides of March: The Conspiracy That Killed Caesar and Destroyed the Republic It Meant to Save

On the morning of 15 March, 44 BC, Julius Caesar walked into a Senate meeting at the Curia of Pompey and never walked out. Sixty senators, men he had pardoned, promoted, and in some cases called friends, had decided he had to die. They believed they were saving Rome. Within two years, the Republic they fought for was further from survival than it had ever been.

A Dictator Who Stopped Pretending

Caesar had spent eight years conquering Gaul for Rome, a campaign that gave him an army, a fortune, and a loyalty few Roman generals could match. When the Senate ordered him to disband that army and come home as an ordinary citizen, he refused. He crossed the Rubicon instead, and the result was civil war. By early 44 BC, with his rivals defeated, Caesar held a title no Roman had ever held outright: dictator perpetuo, dictator for life.

The Roman historian Livy pointed to three specific incidents in 45 and 44 BC as the final triggers of the plot against him. The first came when the Senate marched to the Temple of Venus Genetrix to formally present Caesar with a heap of honors they had voted him. Etiquette demanded he rise to greet them. He didn’t. He even joked that his honors ought to be reduced rather than piled higher. Whether he was physically restrained, as Suetonius later suggested, or simply couldn’t be bothered to observe the courtesy, the message landed the same way: Caesar no longer felt he needed the Senate’s good opinion.

The second incident involved a diadem, the symbol of monarchy that republican Rome had hated since its founding myth. Someone placed one on a statue of Caesar in the Forum. Two tribunes had it removed, and when a crowd later hailed Caesar as “rex” on the road into Rome, he deflected with a pun, “I am not Rex, but Caesar.” The tribunes weren’t charmed. They arrested the man who’d started the chant. Caesar, furious, had the tribunes stripped of office and expelled from the Senate, a move that put him at odds with the plebs who saw their tribunes as the people’s own voice.

The third came at the Lupercalia festival on 15 February, barely a month before Caesar’s death. Mark Antony, his co-consul, placed a diadem on Caesar’s head in front of a crowd. The applause was thin. Caesar took it off. Antony put it back on. The crowd stayed cold. Caesar finally set it aside, declaring that only Jupiter was king of the Romans, and the crowd cheered that. But many in the audience read the whole performance as a test, Caesar gauging whether Rome would accept him as king if he just asked the right way. Suetonius later wrote that fear of exactly this ambition, to be crowned king, was the root cause of the assassination that followed.

Two Men, Then Sixty

The plot began quietly, on the evening of 22 February 44 BC, when Gaius Cassius Longinus sat down with his brother-in-law Marcus Brutus. The two agreed something had to be done to stop Caesar becoming king. From there, they started recruiting.

Brutus insisted the conspiracy needed numbers and standing. For the killing to look like the legitimate removal of a tyrant rather than a grudge settled by a few bitter men, it had to involve a broad swath of Rome’s leading citizens. So he and Cassius screened potential recruits carefully, favoring friends over mere acquaintances, and settling on senators near their own age, around forty, rather than reckless youths or cautious old men. They tested loyalty with carefully innocent-sounding questions before revealing anything. By the time they stopped recruiting, somewhere between sixty and eighty men had joined, though the higher figure may simply be a copying error in the ancient sources.

The conspirators came from surprising directions. Some, like Pontius Aquila, had personal grudges, having been humiliated by Caesar directly. Others, including Decimus Brutus and the Casca brothers, had served under Caesar himself and turned against him anyway. The historian Nicolaus of Damascus suggested that not everyone was driven by lofty principle. Jealousy and unmet financial expectations, resentment that Caesar hadn’t rewarded them enough or had spent too freely on former enemies, pushed some men into the plot as much as any devotion to the Republic.

They weighed in two more names before settling the roster. Cicero, trusted by both leaders and no secret admirer of Caesar’s rule, was ultimately passed over. At past sixty, the conspirators feared he’d choose caution over speed. Mark Antony came up next, but Gaius Trebonius revealed he’d already approached Antony about an earlier plot and been turned down flat. That closed the door.

The Argument That Shaped the Murder

Rejecting Antony as a recruit raised an uglier question: what to do with him instead. One faction, the optimates among the conspirators, wanted a clean sweep, Caesar dead and his whole circle, Antony included, purged along with him, reversing his reforms entirely. Former Caesar supporters who’d joined the plot balked at touching his reforms, but even they were willing to see Antony killed.

Brutus overruled both camps. Killing Caesar alone could be defended as justice against a tyrant, he argued. Killing his supporters too would look like nothing more than a political purge, the kind of bloodletting that would cost them the public’s trust. He believed ordinary Romans objected to Caesar the would-be king, not Caesar the reformer, and that leaving the reforms and the supporters untouched would keep both the people and Caesar’s soldiers from turning on the conspirators afterward. It was a persuasive case. The others fell in line, and from that point the plan narrowed to a single target.

Deciding where and how to strike mattered just as much as deciding who to kill. An assassination in some quiet alley would send a different message than one carried out in the open heart of Rome. The conspirators floated several schemes, an ambush on the Via Sacra, even a plan to topple Caesar off a bridge during consular elections, before the details converged on something bolder: killing him in the Senate itself, surrounded by the very institution he was accused of destroying.

The Fifteenth of March

On that day, in the Curia of Pompey, the conspirators led by Brutus, Cassius, and Decimus Brutus Albinus surrounded Caesar and stabbed him roughly twenty-three times. They called it tyrannicide, the defense of a Republic they said Caesar’s perpetual dictatorship and accumulating honors had put in mortal danger.

It didn’t work. Rather than restoring the old institutions, the killing set off the Liberators’ civil war between Caesar’s avengers and his killers, a war that ground on from 43 to 42 BC. Caesar himself was declared a god after his death. The Republic the conspirators died trying to save instead finished collapsing, and out of its wreckage came the one-man rule of Augustus and the Roman Empire.

What We Still Don’t Know

Even the ancient sources disagree on basic details. The true number of conspirators is uncertain, with ancient tallies ranging from sixty to eighty, and historians suspect the higher figure may be a simple scribal slip. The motives of individual plotters are murky too. Nicolaus of Damascus hints that self-interest and jealousy drove some men as much as principle did, but how many fell into which camp is impossible to say for certain. And the meaning of Caesar’s own conduct in his final months, whether his refusal of the crown at the Lupercalia was sincere restraint or a calculated test of public mood, was debated by Romans at the time and remains unresolved.

Sources

– This article is a synthesis of the Wikipedia article on Assassination of Julius Caesar (en.wikipedia.org/wiki/Assassination_of_Julius_Caesar), which itself cites the underlying scholarship. Readers wanting primary sources should follow that article’s reference list.