The siege of Corfinium was the first significant military confrontation of Caesar's Civil War. Undertaken in February 49 BC, it saw the forces of Gaius Julius Caesar's Populares besiege the Italian city of Corfinium, which was held by a force of Optimates under the command of Lucius Domitius Ahenobarbus. The siege lasted only a week, after which the defenders surrendered themselves to Caesar. This bloodless victory was a significant propaganda coup for Caesar and hastened the retreat of the main Optimate force from Italia, leaving the Populares in effective control of the entire peninsula.