Crossing the Rubicon, Roman Empire

Caesar halts his legions next to the river Rubicon, somewhere in northern Italy, which marks the boundary between Italia and Cisalpine Gaul. After campaigning abroad, a Roman general was obliged to disband his forces before setting foot in his homeland. Failing to do so was to declare war on the Roman people and to become an enemy of the state. 

Yet Caesar knows his orders from the Senate: he is to stand his men down and return home a private citizen. He is to receive no Triumph or honours for his conquests; instead, he will face charges for abuse of power. He will lose his career, his wealth, and perhaps even his life.

He turns to his legions and speaks those three words immortalised by poets over the centuries:

"Alea iacta est"

The die is cast, war has begun. Caesar gives the order and marches on Rome.

Caesar wins Italy quickly. He enters Rome to the acclaim of the people as the optimates flee east to Greece and the Balkans.

War rages across the empire. From Spain to Anatolia, Africa to Gaul, Roman kills Roman. Though civil war has become familiar to the Romans, the scale of the struggle between Pompey and Caesar is unprecedented. This is a global conflict, and few living in the Roman provinces are untouched by the war’s ravages.

At Dyrrachium, in modern-day Albania, Pompey’s forces break Caesar’s siege and deal him a humiliating defeat. But Caesar, after taking Italy, has the momentum, and Pompey does not capitalise on his successes. 

Pompey and Caesar clash again in Pharsalus, their legions meeting in the scrubby fields between the rocky hills of this far corner of northern Greece. Caesar manages to funnel Pompey’s cavalry into the ranks of his reserve infantry, routing them. Caesar’s cavalry then chases them into the hills, leaving the Pompeian flank exposed. The Caesarian horse wheels round to charge. Pompey’s forces are destroyed.

The defeated general flees to Egypt, hoping to secure asylum with Pharoah Ptolemy XIII. Instead, he is met on the landing beach by a group of cutthroats sent by the Pharoah. They decapitate him and send the head to Caesar as a gift. 

Caesar travels to Egypt, furious at the sordid killing of his rival. Here he finds another powerful kingdom in civil war. The marriage between the magnificent Cleopatra VII and her kid brother Ptolemy has broken down, and the two struggle for the Egyptian throne. Caesar takes the side of Cleopatra and, at the Battle of the Nile, destroys Ptolemy’s forces. Cleopatra becomes the sole Pharaoh of Egypt and begins a love affair with the Roman, bearing him a son known to us today as Caesarion (meaning ‘Little Caesar’). Rome’s most powerful family is now intertwined with the Ptolemies, the Greek dynasty that rules Egypt.

The other optimates led by Cato and Scipio make their final stand at Thapsus, near Carthage. Scipio gives battle where his ancestors had conquered, ready to lay his life down for the Republic. Though the optimates’ forces fight heroically, they are easily dispatched. A final battle takes place against Pompey’s sons at Munda and then it is over.

Though Caesar extends his hand in peace, offering a pardon to many who took up arms against him, the optimates prefer death to dishonour. Cato disembowels himself near Utica, Scipio is captured and pressured into suicide, and Pompey's son Sextus takes to the seas to live as a pirate. Caesar has conquered and, in 44 BCE, he names himself dictator for life.

With the victory of Caesar over the optimates, the Republic is effectively dead. Caesar now has power that goes beyond that of a monarch. For the first time since the banishing of King Tarquinius Superbus, one-man rule has returned to Rome.