The battle of the Bagradas River (24 July 49 BC) was a major defeat for Caesar's army in North Africa, and firmly established Pompey's control over the area (Great Roman Civil War).
At the outbreak of the Great Roman Civil War Caesar swept down the Italian peninsula, capturing Rome and forcing Pompey and most of the Senate to flee east to Greece. This left Caesar in command of Italy, Gaul and Illyricum, while Pompey controlled Greece and the east, Spain and North Africa.
Caesar decided to lead his main army against Pompey's forces in Spain, while a second army, under G. Scribonius Curio, was sent to secure Sicily and North Africa. Curio was given four legions for this task, including two that had only recently changed sides, coming over to Caesar at Corfinium during his march down Italy. After successfully taking control of Sicily, Curio decided to lead these two legions and 500 cavalry across to North Africa.
Pompey had three legions in North Africa, under the command of P. Attius Varus. He could also rely on support from King Juba of Numidia, who had a grudge with Caesar for sheltering one of his local rivals, and with Curio who had once proposed a law that would have turned Numidia into a Roman province.
Curio's expedition began well. He landed near Cape Bon and advanced west towards Utica. He left his legions at the Bagradas River and conducted a successful cavalry raid towards Utica. He then moved the legions north to Utica, where he won a short battle against Varus close to the city (battle of Utica). In the aftermath of this defeat Varus was forced to retreat into the city, which Curio then besieged (siege of Utica). This was a short siege, for news soon reached Curio that King Juba was only twenty miles from the city. Curio's initial response was very sensible. The siege was abandoned and he retreated to the Cornelian camp, a strong position on the coast that had been used by Publius Cornelius Scipio Africanus during his siege of Utica 150 years earlier. The two legions still in Sicily were ordered to cross over to Africa, and Curio prepared to hold out until their arrival.
Caesar and Appian both provide us with accounts of the battle, differing in the early stages but essentially similar. In both accounts Curio is tempted into his fatal advance by reports that the King had been forced to return home with most of his men, leaving a small force under his general Saburra at the Bagradas. In Caesar's account Curio sent his cavalry to attack Saburra's camp, and then followed behind with most of his infantry. The Roman cavalry won a victory over Saburra's men and then returned to Curio with their prisoners. Curio asked who commanded their camp, and the prisoners answered 'Saburra', further confirming Curio's view that he only faced part of the Numidian Army. This encouraged Curio to continue his march, even though most of the cavalry was exhausted after their nights work and fell behind.
At this point the two accounts differ. According to Appian Curio reached the River Bagradas, where he found the entire Numidian army. Discouraged by this he retreated onto some nearby high ground, allowing the Numidians to cross the river. Curio then came down from the hill to offer battle. His force was soon surrounded by the Numidian cavalry and compressed into an ever smaller space. An attempt to reach safety on the hills failed. Some of the stragglers managed to escape back to the camp near Utica, but Curio and most of his men were killed.
In Caesar's account Curio ran into Saburra's men first. At this point Juba was several miles away, although he had already sent 2,000 Spanish and Gallic cavalry to support his general. Saburra slowly gave way as the Romans advanced, drawing Curio closer to Juba. This feigned retreat went on for sixteen miles before the Romans became exhausted and were forced to stop. At this point Saburra stopped his retreat and went onto the attack.
At this point Caesar's account matches Appian again, but with more detail. The Numidian horse was soon able to defeat the outnumbered Roman cavalry. The Roman infantry was surrounded, with enemy cavalry attacking their flanks and rear. The Numidians were now receiving a stream of reinforcements from Juba, and the Romans were becoming increasingly exhausted. Curio made an attempt to lead his men onto some nearby hills, send the legion's standards towards the high ground. This attempt failed because Saburra had already posted some of his cavalry on the hills. Curio refused to try and escape from the trap, and was killed along with all of his infantry. Some of the cavalry escaped, mostly those who had fallen behind during the advance.
The few survivers of the battle managed to escape back to the Cornelian camp, but this was no safe haven. Curio's fleet escaped, leaving the remaining soldiers trapped. They surrendered to Varus, but on the following day Juba arrived at Utica, seized the prisoners and killed most of them.
The defeat on the Bagradas River ensured that Pompey and his allies would retain control of North Africa, and would give them somewhere to rally after their main armies were defeated at Pharsalus in August 48 BC.