Ides of March Denarius (EID MAR)

The EID MAR denarius is arguably the most famous coin from antiquity. Issued in the name of Marcus Junius Brutus, one of the principal assassins of Julius Caesar, it openly celebrates the killing of a Roman dictator on a piece of circulating money — an act of political propaganda without real parallel in the ancient world.

Only a small number of examples are known today, split between silver denarii and an even rarer handful of gold aurei. Because the coin ties directly to one of history's most consequential events, it commands intense interest from both ancient coin specialists and general collectors of historic artifacts.

Brutus had these coins struck in 42 BC, in the months before his defeat at the Battle of Philippi, using a traveling military mint that moved with his army through Greece and western Asia Minor as he raised funds and troops against Mark Antony and Octavian. The issue was meant to justify the assassination as an act of liberation from tyranny rather than murder.

The moneyer named on the coin, alongside Brutus himself, was Lucius Plaetorius Cestianus, an officer responsible for overseeing the strike. Brutus's decision to place his own portrait on the obverse was itself notable, since living Romans rarely appeared on coinage before Caesar had broken that taboo.

After Philippi in 42 BC, Brutus died and the Republican cause he championed collapsed, but the coin survived as a permanent record of the conspirators' justification, ensuring the EID MAR issue would be remembered long after the men who struck it were gone.

The obverse shows a right-facing portrait of Brutus with the legend BRVT IMP around it and L PLAET CEST below, naming the moneyer. The reverse is the coin's most distinctive feature: a pileus, the soft cap traditionally given to freed slaves as a symbol of liberty, positioned between two unsheathed daggers, with the legend EID MAR (short for Eidibus Martiis, 'on the Ides of March') beneath.

Genuine examples are struck in silver on a standard Roman denarius flan, roughly 18-19mm in diameter and about 3.5-3.9 grams; the exceptionally rare gold aureus version is smaller in size but far greater in value. Because the design has been extensively studied and forged, any claimed example should be evaluated by specialists experienced with Roman Republican coinage and its known die varieties.

The EID MAR type is a legendary rarity: only a couple dozen silver denarii are recorded and just a tiny handful of gold aurei exist, one of which sold at auction for well over two million dollars in 2020, making it one of the most expensive ancient coins ever sold. Even well-worn silver denarii, on the rare occasions they appear at auction, typically bring hundreds of thousands of dollars given their fame and historical weight.

Condition matters less for this issue than authenticity and pedigree, since so few genuine specimens exist and each has usually been individually published and tracked through major auction houses. Because of the coin's fame, modern fakes and casts are common, so any potential example needs rigorous expert authentication before any value can be reasonably estimated.