The Battle of Ilerda took place in June 49 BC between the forces of Julius Caesar and the Spanish army of Pompey the Great, led by his legates Lucius Afranius and Marcus Petreius.

Caesar also took the chance to attack Afranius's foragers, sending most of his cavalry onto the east bank of the river, where they captured a large number of cattle.Over the next few days the two armies manoeuvred around in the rough ground north of the Ebro, Afranius attempting to reach the river and Caesar attempting to gain control of the key valleys leading south. Toujours cependant ils se soutenus par leur courage et leur patience, et ne sont pas découragés par les nombreuses blessures qu'ils ont reçues. Caesar was relying on supply convoys from Italy and Gaul, and these were now stuck on the wrong side of the river. Engraving of 'History of Spain'.

Mais les soldats de la neuvième légion, exaltés avec succès, et désireux de réparer la perte que nous avions soutenu, suivi les fuyards avec tant de chaleur qu'ils ont été attirés dans un lieu de désavantage, et se trouve directement sous la colline où la ville était , d'où ils se sont efforcés de quand prendre leur retraite, l'ennemi face à nouveau au sujet, chargé avec vigueur à partir du sol supérieur. This he achieved through an impressive feat of engineering, digging a series of thirty-foot deep drains with which he intended to divert the course of the River Segre. Those soldiers with lands or other possessions in Spain were allowed to leave immediately, while the rest would be escorted to the River Var. Six cents plus de blessés. Lucius Plancus, the commander of the two legions, took up a position on a nearby hill, where he was soon attacked. Afranius and Petreius themselves both made their way to join Pompey's main army in the Balkans, where they would continue to fight on against Caesar.Two days later Caesar arrived at Fabius's camp and took command. Ceci, combiné avec leur technique de combat comme escarmouche, submergé le détachement Césarienne et ses troupes ont été contraints de céder du terrain, éventuellement en retraite à la sécurité.César, contrairement à son attente, trouver la consternation comme à se répandre dans toute l'armée, a encouragé ses hommes, et a conduit la neuvième légion à leur secours. According to Caesar's account of the battle his infantry approached him and offered to try and ford the river. He attempted to make a stand at Gades, but as Caesar advanced across Spain towards him his army dissolved, and eventually he submitted peacefully.