The issuers of this Roman denarius were Marcus Junius Brutus and Publius Servilius Casca Longus. They both belonged to the conspirators against Julius Caesar, who had been murdered in 44 BC.
After the assassination the conspirators had to leave Rome. Brutus and Casca went to Greece, where they recruited troops to prepare for the war against Mark Antony and Octavian, the remaining powerful men in Rome. To pay the mercenaries, Brutus and Casca minted coins.
This denarius is one of these coins. It shows on the obverse Neptune, the god of the sea with a trident over his shoulder, and on the reverse Victory with a palm-branch. The goddess tramples on a scepter and crushes a royal diadem. These were strong symbols against kingship.
In the end, the Republicans did not succeed. After a lost battle at Philippi in 42 BC, Brutus and Casca committed suicide. Some years later the Republic perished, and from its ashes arose the Roman Empire.