One of my most precious possessions is a small Roman coin. It is a tiny sliver of silver, a denarius minted in 43 BCE in Asia Minor for the army of Brutus: yes, that Brutus, assassin of Julius Caesar, the addressee in “et tu, Brute?”.

Along with his fellow assassin Cassius, Brutus had fled to Asia in the aftermath of Julius Caesar’s assassination, and he was busy collecting troops and money so that he could fight Mark Antony and Octavian (later Rome’s first Emperor, Augustus) for control of the Roman Republic. This coin would have been used to pay his troops, and he entrusted the task of minting it to a junior official, Lucius Sestius.

The head on the coin is that of the goddess Liberty, with Sestius’ name around the edge.

With this imagery, Brutus was justifying his assassination of Caesar – he had made a sacrifice to Liberty, with Caesar as sacrificial victim. If we dig a little deeper, we discover that Brutus also sacrificed his personal friendship with Caesar. An interesting connection is that Brutus’ mother, Servilia, was Caesar’s favourite mistress, and Brutus himself had been favoured by Caesar, giving rise to the rumour that he was Caesar’s son. But he was persuaded, probably by Cassius, that Caesar was too much of a threat to Rome.

This decision had the potential to demand sacrifices of the women of Brutus’ family: we do not know how his mother felt at the death of her lover, but it is hard to think that she was unmoved. Brutus had three half-sisters, with the two elder sisters married to supporters of Caesar. How did these women view their brother’s act? The youngest sister, Junia Tertia, was married to his friend Cassius. In May 44 BCE, barely two months after the Ides of March, she suffered a miscarriage, and it is impossible not to wonder if the stress and fear following the Ides played a part.

The strange implements on the coin’s other face are the instruments of sacrifice – a tripod, a ritual ladle, an axe.

Brutus’ final sacrifice came at the Battle of Philippi: when he realised that he had lost, he committed suicide.

Now for the other man who put his name on this coin. Lucius Sestius Quirinalis is not a famous Roman, but he pops up in our sources several times. His family were friends with Cicero, and his father was lucky enough to have Cicero defending him in a politically charged trial. Dig around, and you will find out that Lucius survived the Battle of Philippi, and twenty years later was honoured by the man against whom he fought – the emperor Augustus. The historian Cassius Dio tells us:

“Augustus appointed as consul Lucius Sestius– a man who had worked and fought for Brutus and even now honoured Brutus’ memory. Not only did Augustus not begrudge Sestius’ loyalty and affection for Brutus, he even honoured it.”

I made Lucius Sestius the hero of my trilogy because I saw him as an Everyman, involved, but never important enough to be given the headlines. Through him, I could trace Rome’s descent into civil war after the Ides, and her renaissance through Augustus.

And back to the coin – it is beginning to tarnish now, but that is how I shall leave it. It represents an unhappy time.

Fiona Forsyth is a novelist and the author of Rome’s End, a Lucius Sestius Mystery.