After Caesar departed for Dyrrhachium with most of his army, Gnaeus Pompeius the younger attacked Oricum with his fleet, and overcoming the harbour defenses prepared by Marcus Acilius Caninus, took the city by storm.
[1][2] On January 4, 48 BC,[i] Caesar embarked from Brundisium with seven legions and six hundred select cavalry, which he carried on merchant ships, as his small number of warships was guarding Sardinia and Sicily against any approach by the Pompeians.
[14][1] Surrounded by hostile forces, Oricum was attacked from ship-mounted towers, while Pompeius' soldiers assaulted the walls using scaling ladders, constantly replacing his men with fresh troops, until the weary defenders capitulated.
[14][16] Having retaken Oricum, Pompeius left Decimus Laelius, detached from his father's Asian fleet, in command of a squadron charged with keeping Caesar's forces from being resupplied from Byllis and Amantia.
[14][10] He then proceeded to Lissus, where he burned a fleet of transports left there by Marcus Antonius, but he was unable to overcome the defenses of Caesar's garrison, and failed to take the town itself, retiring with significant losses after a siege of three days.