The battle of Ruspina (46 BC) was a minor defeat suffered by Caesar soon after he arrived in Africa, but his Republican opponents failed to take full advantage of their success, and allowed Caesar to recover from the early setback (Great Roman Civil War).
In the aftermath of his victory over Pompey the Great at Pharsalus (9 August 48 BC), Caesar pursued Pompey across the eastern Mediterranean. Pompey attempted to escape to Egypt, where he hoped to find allies, but instead he was killed at the orders of the advisors of the young Ptolemy XII. Caesar arrived a few days later, and was soon dragged into Egyptian politics. He was soon besieged in Alexandria (August 48-January 47 BC), giving his Republican opponents the chance to recover from their defeat.
Most of the remaining Republican leaders fled to the province of Africa, where they soon built up an impressive army. Moral leadership came from Cato the Younger, one of Caesar’s most determined opponents. Metellus Scipio, a former Consul and the most senior man remaining, was acknowledged as the commander of the Republic forces, although Caesar’s former officer Labienus was probably the military leader. The Republicans also gained the aid of King Juba of Numidia. By the time Caesar was ready to move to Africa, the Republics had ten legions of their own, four legions and a large number of light troops under, 120 elephants and a large fleet.
After finally escaping from Alexandria, Caesar had to return to Asia Minor to deal with Pharnaces, king of the Cimmerian Bosporus, the son of Mithridates the Great of Pontus. Pharnaces was quickly defeated at Zela, allowing Caesar to return to Rome. Once he had settled affairs in the capital, he moved south to deal with the Republicans in Africa. He ordered his army to gather on Sicily, where he eventually gathered six legions and 2,000 cavalry.
Caesar crossed over to Africa at the start of January 46 BC. His transport ships were badly scattered during the crossing, and for some time he was dangerously isolated on the North African coast. He established a base at Ruspina, where he was eventually joined by many of the missing ships.
Most of the sources mention some sort of setback for Caesar. Plutarch suggests that there were several, and that they encouraged Scipio to risk the final battle that saw him defeated.
Appian has Caesar deploying his forces near to Scipio’s camp while Scipio was absent. Labienus attacked and defeated him, but ended the pursuit after Labienus’s horse was wounded. Marcus Petreius, his co-commander, withdrew, claiming that he didn’t want to deprive Scipio of the victory. There is no location given in this account, but the incident with the horse is repeated in the African Wars account of a clash at Ruspina.
The African Wars, probably written by one of Caesar’s officers, gives the longest account of the fighting. After the missing ships had arrived, Caesar decided to lead thirty cohorts out to forage. Three miles outside their camp they ran into an enemy force led by Labienus and the two Pacidii (obscure members of an obscure family). They had a large force of cavalry, mixed in with lightly armed Numidians and archers. This force deployed in close order, convincing Caesar’s men that they faced a large force of infantry.
Caesar deployed his small force in a single line, with his 150 archers in front and his 400 cavalry split between the two wings. He was still expecting to face infantry, and so it came as an alarming surprise when the Republican cavalry began to extend their lines in an attempt to surround Caesar’s cavalry. In the meantime Caesar’s infantry came under dart attack, as the lightly armed Numidians and cavalry in the Republican centre began to harass them. Caesar’s men attempted to catch the cavalry, but only made themselves vulnerable to the darts of the light infantry. Caesar’s cavalry was then forced to retreat, and his infantry was soon surrounded and was forced to form a circle.
At this point we get the story of Labienus’s wounded horse. This time it came during a confrontation between Labienus and a veteran of the Tenth Legion, whose unit was in disgrace. The legionary threw his javelin and wounded Labienus’s horse. However in this account this didn’t end the battle.
Caesar responded to being encircled by extending his line and ordered his cohorts to face alternately to the right and left, to produce a double sided line. As his wings extended, they broke the circle, and even managed to catch some of the enemy cavalry isolated and foce them to flee. However Caesar was unable to push too hard, and ordered a retreat back towards camp.
At this point the Republicans received reinforcements - 1,100 Numidian horse and a large force of light infantry, commanded by Petreius and Cn. Piso. The Republics attacked Caesar’s retreating legions, forcing them to turn and fight. Caesar ordered a counterattack, which is claimed to have forced the enemy into a full scale retreat. However it probably just stopped the immediate attack, allowing Caesar to complete the retreat back to his camp.
The success at Ruspina encouraged Scipio, who now believed that his army could defeat Caesar in an open battle. After a series of inconclusive clashes, the two armies fought at Thapsus (February 46 BC), the decisive battle of the campaign. Caesar was victorious, and the last major Republican army had been defeated.