Battle of DyrrhachiumDurrës, Albania
Caesar attempted to capture the vital Pompeian logistics hub of Dyrrachium but was unsuccessful after Pompey occupied it and the surrounding heights. In response, Caesar besieged Pompey's camp and constructed a circumvallation thereof, until, after months of skirmishes, Pompey was able to break through Caesar's fortified lines, forcing Caesar to make a strategic retreat into Thessaly.
In a broader sense, the Pompeians elated at the victory, being the first time in the civil war that Caesar had suffered a non-trivial defeat. Men like Domitius Ahenobarbus urged Pompey to bring Caesar to decisive battle and crush him; others urged a return to Rome and Italy to retake the capital. Pompey remained steadfast in believing that committing to a pitched battle was both unwise and unnecessary, deciding on strategic patience to wait for reinforcements from Syria and to exploit Caesar's weak supply lines. The elation of victory turned into overconfidence and mutual suspicion, putting significant pressure on Pompey to provoke a final encounter with the enemy. Beginning to place too much trust in his forces and under the influence of overconfident officers, chose to engage Caesar in Thessaly shortly after being reinforced from Syria.