Rare 'Ides of March' dagger coin minted by Brutus after Julius Caesar's murder goes to auction

A silver coin against a white background. The coin has two daggers and a hat between them. It says EID MAR for the ides of march.
The "tails" side of the silver coin shows two daggers and a freedman's cap, symbolizing how Brutus freed Rome from Julius Caesar. (Image credit: Stack's Bowers Galleries)

Just two years after Julius Caesar's murder in ancient Rome, one of his assassins minted a coin celebrating the would-be dictator's death, with daggers emblazoned on its "tails" side. Only about 100 of these coins survive today, and now a rare silver specimen is going to auction this month. 

The coin, known as an "EID MAR" denarius that commemorates the Ides of March, was minted in 42 B.C. by Marcus Junius Brutus, the man who famously assassinated Julius Caesar.

Caesar became an extremely powerful politician in the Roman Republic by 50 B.C., when, as head of the military, he racked up Roman victories in the Gallic Wars, extending Rome's territory into France. After his success, Caesar was asked by the Roman senate to step down from his military command. But Caesar refused and crossed the Rubicon river with his army, sparking a civil war that he eventually won and putting himself in an unparalleled position of power in 44 B.C., when he declared himself "dictator in perpetuity."

That year, many politicians were concerned that Caesar, not content with being dictator, wanted to become a king. A plot formed among a group of Roman senators to assassinate Caesar, which they accomplished by stabbing him multiple times on March 15, or the Ides of March.

We see the profile of Brutus, one of Julius Caesar's assassins. Along the edges are the words BRUT IMP, for Commander Brutus, and PLAET CEST for the coin's minter, Lucius Plaetorius Cestianus. (Image credit: Stack's Bowers Galleries)

But Caesar's death wasn't the political home run his assassins expected, as many people didn't welcome the news. Brutus and Cassius, the co-conspirators in the assassination plot, fled Italy and took control of the eastern provinces from Greece to Syria. Meanwhile, the leaders who controlled the Roman army were Caesar's allies: his colleagues Mark Antony and Marcus Lepidus, as well as his grand-nephew and heir Octavian. A civil war ensued between these two forces from 43 B.C. to 42 B.C., culminating in Antony and Octavian avenging Caesar's death at the Battle of Philippi in Greece, defeating Brutus and Cassius, who took their own lives rather than surrender.

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The silver EID MAR denarius — a Roman coin worth about a day's pay — was minted by Brutus during the Battle of Philippi as a means of paying his soldiers. On the obverse, or "heads" side, there is a bust of Brutus and the inscription "BRUT IMP," meaning Commander Brutus, in addition to the name of the man who minted the coins. The reverse, or "tails" side, of the coin bears the abbreviation "EID MAR," meaning the Ides of March, along with two daggers and a freedman's cap, symbolizing how Brutus freed Rome from Caesar.

"Prior to Julius Caesar in 44 BCE, no living Roman had ever put his own portrait on a Roman coin," Liv Yarrow, a history professor at Brooklyn College in New York who is an expert on coins of the Roman Republic, told Live Science. "Traditionally, [coin] heads were reserved for gods and kings," she said. This, coupled with Caesar's declaration of himself as dictator in perpetuity, directly led to his assassination. 

While Brutus seems to be claiming to have freed the Romans from Caesar as king, he also hypocritically "promotes himself and his own image on the other side of the coin using the same sort of self-fashion as Caesar, the would-be autocrat," Yarrow said.

There were more than 25 different reverse "tails" dies that were used to create the silver EID MAR coin. Each die pair could mint roughly 10,000 to 20,000 coins, so hundreds of thousands were probably made. Most of the coins of this type have been found in Greece, but they have also surfaced in Romania, France, Italy and the U.K., and appear to have been in circulation until at least 4 B.C.

The EID MAR silver denarius that is newly up for auction is expected to fetch up to $300,000, according to Stack's Bowers Galleries, which is offering it for sale. If it were a slightly more attractive example, the auction house noted, it could go for more than double that.

Rarer still is the gold EID MAR coin; only three examples are known to exist in the world. One of these coins sold in October 2020 for $4.2 million, the most ever paid for an ancient coin. However, the coin was returned to Greece in March 2023, after investigators discovered that it was looted, making the sale fraudulent.

The Stack's Bowers Galleries silver EID MAR denarius is scheduled to be auctioned off on Aug. 15.

Kristina Killgrove
Live Science contributor

Kristina Killgrove is an archaeologist with specialties in ancient human skeletons and science communication. Her academic research has appeared in numerous scientific journals, while her news stories and essays have been published in venues such as Forbes, Mental Floss and Smithsonian. Kristina earned a doctorate in anthropology from the University of North Carolina at Chapel Hill and also holds bachelor's and master's degrees in classical archaeology.