Petreius

Family: Pompeian · Role: commander · First appears: The Civil War, Book I, 34–40

In Book I of The Civil War, Petreius served as one of Pompey’s lieutenants in Spain. After Vibullius Rufus arrived, Petreius and Lucius Afranius divided the Spanish departments with Marcus Varro. Petreius marched through the Vettones to join Afranius, and together they chose to wage war near Ilerda. When a bridge collapse cut off Caius Fabius’s cavalry, Afranius crossed the river with four legions to attack Fabius’s two.

Later, Petreius and Afranius resolved to transfer the war to Celtiberia, ferried two legions across the Segre, and fortified a camp at Octogesa. Seeing Caesar’s forces approach, they halted and drew up their army; when Caesar’s signals made them fear a night engagement, they stopped their march and stayed in camp. Their council decided to set out at dawn, but after Caesar declined battle, Petreius and Afranius withdrew. The following day they divided the work of building a rampart from their camp to the water.

As Afranius’s soldiers negotiated with Caesar’s men, they sought guarantees for the lives of Petreius and Afranius and promised to remove their standards. Petreius interrupted the talks, drove Caesar’s men from the camp, and killed those he caught. He then required the soldiers to swear not to desert or betray the army or its generals, swore the oath himself, and obliged Afranius to take it.