2 August 47 BC – Battle of Zela

2 August 47 BC – Battle of Zela

“Veni, vidi, vici” (“I came, I saw, I conquered.”) (Gaius Julius Caesar)

Roman Empire

In the mid-First Century BC the Mediterranean world was in the throes of civil war. 49 BC had seen Gaius Julius Caesar, the hugely popular conqueror of Gaul, call the bluff of the Senate that sought to strip him of his imperium and tear away his prestige. His swift invasion had been followed by a campaign in Greece which had begun with defeat before seeing him crush the huge army of the great general Pompey Magnus at Pharsalus in 48 BC.

Caesar chased the defeated Pompey to Egypt, itself in the grip of civil unrest, only to find that the advisors of Ptolemy XIII had made the mistake of thinking it a good idea to kill Caesar’s great rival and present the dictator with his head. Denied the chance to show his magnanimity through his customary clemency, Caesar took the opportunity to meddle in Egyptian affairs. His few troops survived the Siege of Alexandria before defeating the Egyptians at the Battle of the Nile in 47 BC, in which the young pharaoh was killed. Caesar spent much of the summer uncharacteristically lingering on the Nile with Cleopatra, who became pregnant with his son, Caesarion.

reliefs of Cleopatra and Caesarion at the Temple of Dendera Right: a limestone stela of the High Priest of Ptah bearing the cartouches of Cleopatra and Caesarion, Egypt, Ptolemaic Period, the Petrie Museum of Egyptian Archaeology, London

While Caesar was idle, his enemies were active. Cato the Younger was organizing the survivors of Pharsalus into a new base of resistance to the dictator near Carthage (Tunis), while many of Pompey’s veterans were still active in Hispania. In Asia Minor (Asian Turkey) there was lingering resentment against Rome in the Euxine (Black) Sea kingdom of Pontus. Only a generation earlier Mithridates VI the Great “Eupator” had driven the Romans out of Asia to much applause, hated as they were for their heavy-handed tax collecting which allowed contractors free reign to squeeze whatever tax they could out of a province, condemning many people to poverty and slavery. So vehement was the shared hatred of Rome that the Asian cities were complicit in Mithridates’ great genocide where he organised a set day for all Roman citizens to be murdered, with more than 80,000 believed dead.

Mithridates had previously clashed with Rome as they opposed his expansion into neighboring regions like Cappadocia and Bithynia, still nominally independent kingdoms that were essentially vassals of Rome. He chose bizarre timing to launch this war though, allowing the Romans to settle the devastating Social War so they could turn their resources to focus on him just as he crossed the Aegean to seize control of Greece too.

This all took place to the backdrop of the great rivalry between Gaius Marius and Lucius Cornelius Sulla which saw the latter originally abandon his expedition to Greece to march on Rome after Marius sent emissaries to arrest him, before he finally departed with Marius inevitably returning in his absence to seize the Eternal City. Sulla would crush Mithridates in that campaign to shatter Pontic hopes for challenging Rome, before the years to follow would see his forces smashed again as Pompey campaigned in the east.

Following his victory at Pharsalus, Caesar had left Calvinus in command of the legions of Asia Minor during his pursuit of Pompey. These men were largely veterans of Pompey’s disbanded legions, and with them set up Caesar had left the province to head to Egypt. Sensing an opportunity to return Pontus to its pedestal, Pharnaces decided to expand his kingdom, and in 48 BC invaded Cappadocia, Bithynia and Armenia. Despite being outnumbered, Calvinus advanced into Pontus with three legions and auxiliaries, raising further troops from Rome’s Pontic settlers.

Pharnaces failed to delay Calvinus with diplomacy, and after falling back to Nicopolis saw his ambush thwarted too. The Pontic army assembled between two trenches, and Calvinus thinned his line to match the length of the larger Pontic force. The Battle of Nicopolis started poorly for Rome when her recently levied Pontic troops in the center broke, leading to them having to retreat. Only the steadiness of his veteran legion prevented a complete rout for Calvinus, though by the time he had retreated around two thirds of his army had been lost, with Pharnaces triumphant.

A subsequent rebellion that broke out in Pontus prevented Pharnaces from annihilating the retreating Romans, though he dealt with it harshly. In his anger he looked to repeat his father’s genocide, and began to execute any Roman prisoners and Italian civilians he came across, though had some of the men castrated and allowed to escape to Rome instead to tell of the atrocity. The only thing that prevented this horror being a repetition of what his father had committed was that the depopulated region had far fewer Italians living in following years of instability.


By the time Pharnaces had quelled the rebellion, Caesar had arrived in Asia Minor with two legions – around half the strength of the Pontic army. Pharnaces sent emissaries to attempt peace with the Romans, though Caesar refused this outright. Pharnaces set up camp near the hilltop town of Zela where his father had won a great victory two decades earlier. He had a strong defensive position with a track linking him to the mountain. Caesar marched his force to the opposite side of the valley, at which point Pharnaces lined his troops up in battle order. Caesar had around 15,000 of his veteran legionaries, while Pharnaces had around 20,000 Pontic troops.

Caesar’s men were setting up the camp still when they saw Pharnaces riding in front of his vanguard of scythed chariots. The Pontic host began to move down into the valley and up against the Roman camp. Caesar was caught napping, with the Pontic attack defying logic by choosing to attack a fortified position uphill. With most of the legions still in camp, the small force outside was pressed hard by the attacking Pontic troops. Legionaries dropped their spades and shovels to grab their shields and swords as they rushed to reinforce the defense of the camp against the sudden attack.

Caesar himself rushed out of the camp to rally his men, encouraging a counterattack which earnt the space for the rest of the legions to exit the camp. While the scythed chariots broke through the initial line, they were swiftly felled by a hail of Roman javelins as more legionaries poured out of the camp and into the fray. The veteran legions now pushed the Pontic troops down the hill, slaughtering them as they went, and in the ensuing chaos went up the opposite hill, capturing the enemy camp. Caesar’s campaign against Pharnaces had lasted less than five hours since first contact. The Pontic king escaped the rout, only to be killed in a skirmish on the return to his Bosporan Kingdom (Crimea). Caesar’s campaign had been so swift, that after the battle he famously declared: “Veni, vidi, vici” (I came, I saw, I conquered).

The battle was over, but Caesar still faced challenges to his authority.

The following year would see him suffer a setback at the start of his African campaign before crushing the followers of Cato at Thapsus, completing his control of the republic with a triumph over the sons and veterans of Pompey in Hispania at Munda a year later. He had great designs to reform the Roman structure, including introducing a new calendar, and planned to campaign deep into Persia to avenge the defeat of his previous fellow triumvir Marcus Crass by the Parthians at Carrhae a decade earlier.

These plans would never be realized though, for while Caesar could not be bested on the battlefield his opponents instead chose the Senate floor to murder him, naively hoping to restore the republic. Instead, they unleashed the ambition of his adjutant Mark Antony, and the unknown teenager would surprise the world by naming him as his heir. That heir was Octavian, who would go on to show far less clemency than his adoptive father as he crushed all opposition to secure his grip as Rome transitioned from republic to empire under Augustus.

Written by Jack Tappin

Written by Jack Tappin

Roman Empire

2 August 47 BC – Battle of Zela