Caesar attempted to capture the vital Pompeian logistics hub of Dyrrachium but was unsuccessful after Pompey occupied it and the surrounding heights.

Starting in January with a lightning advance against the Pompeian and senatorial forces in Italy, Pompey withdrew across the Adriatic for Rome's eastern provinces.

[2] At Dyrrachium, Pompey held a strong defensive position; his back was guarded by the sea, and at his front there were hills that commanded the immediate area.

There, Pompey established his camp on the top of a rocky outcrop called Petra overlooking a natural harbour from which he could be resupplied by sea.

[12] Pompey decided to try and lure Caesar away from the fortifications by means of a false message that some of the inhabitants of Dyrrachium were prepared to betray the town to him, and meanwhile launch a three-pronged attack against forts in the centre of the siege-line.

[20] 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.

[20] The elation of victory turned into overconfidence and mutual suspicion, putting significant pressure on Pompey to provoke a final encounter with the enemy.

[21] Beginning to place too much trust in his forces and under the influence of overconfident officers, he chose to engage Caesar in Thessaly shortly after being reinforced from Syria.