This is a denarius serratus, a toothed denarius of the Roman Republic. It was emitted in the year 118 BC and shows on its obverse the head of Roma, the goddess and personification of Rome. Behind her is the mark X for the coin's value of 10 asses. The inscription around Roma denotes the abbreviated names of several moneyers responsible for the issue of this coin.
The reverse depicts a naked Gaulish warrior in a two-horse chariot. The warrior is equipped with a shield, a spear and a carnyx, a Celtic wind instrument. Below the horses is L. LIC. for the moneyer Lucius Licinius Crassus and CN. DOM. for his colleague Gnaeus Domitius Ahenobarbus.