But, even as it was, these days were fraught with mischief. Not only had Caesar endured the most serious losses and forfeited at a blow his entrenchments, the result of four months of gigantic labour; he was by the recent engagements thrown back again exactly to the point from which he had set out. From the sea he was more completely driven than ever, since Pompeius' elder son Gnaeus had by a bold attack partly burnt, partly carried off, Caesar's few ships of war lying in the port of Oricum, and had soon afterwards also set fire to the transport fleet that was left behind in Lissus; all possibility of bringing up fresh reinforcements to Caesar by sea from Brundisium was thus lost. The numerous Pompeian cavalry, now released from their confinement, poured themselves over the adjacent country and threatened to render the provisioning of Caesar's army, which had always been difficult, utterly impossible.

Caesar's daring enterprise of carrying on offensive operations without ships against an enemy in command of the sea and resting on his fleet had totally failed. On what had hitherto been the theatre of war he found himself in presence of an impregnable defensive position, and unable to strike a serious blow either against Dyrrhachium or against the hostile army; on the other hand it depended now solely on Pompeius whether he should proceed to attack under the most favourable circumstances an antagonist already in grave danger as to his means of subsistence. The war had arrived at a crisis. Hitherto Pompeius had, to all appearance, played the game of war without special plan, and only adjusted his defence according to the exigencies of each attack; and this was not to be censured, for the protraction of the war gave him opportunity of making his recruits capable of fighting, of bringing up his reserves, and of bringing more fully into play the superiority of his fleet in the Adriatic. Caesar was beaten not merely in tactics but also in strategy. This defeat had not, it is true, that effect which Pompeius not without reason expected; the eminent soldierly energy of Caesar's veterans did not allow matters to come to an immediate and total breaking up of the army by hunger and mutiny. But yet it seemed as if it depended solely on his opponent by judiciously following up his victory to reap its full fruits.

It was for Pompeius to assume the aggressive; and he was resolved to do so. Three different ways of rendering his victory fruitful presented themselves to him. The first and simplest was not to desist from assailing the vanquished army, and, if it departed, to pursue it. Secondly, Pompeius might leave Caesar himself and his best troops in Greece, and might cross in person, as he had long been making preparations for doing, with the main army to Italy, where the feeling was decidedly antimonarchical and the forces of Caesar, after the despatch of the best troops and their brave and trustworthy commandant to the Greek army, would not be of very much moment. Lastly, the victor might turn inland, effect a junction with the legions of Metellus Scipio, and attempt to capture the troops of Caesar stationed in the interior.

The latter forsooth had, immediately after the arrival of the second freight from Italy, on the one hand despatched strong detachments to Aetolia and Thessaly to procure means of subsistence for his army, and on the other had ordered a corps of two legions under Gnaeus Domitius Calvinus to advance on the Egnatian highway towards Macedonia, with the view of intercepting and if possible defeating in detail the corps of Scipio advancing on the same road from Thessalonica. Calvinus and Scipio had already approached within a few miles of each other, when Scipio suddenly turned southward and, rapidly crossing the Haliacmon (Inje Karasu) and leaving his baggage there under Marcus Favonius, penetrated into Thessaly, in order to attack with superior force Caesar's legion of recruits employed in the reduction of the country under Lucius Cassius Longinus.

But Longinus retired over the mountains towards Ambracia to join the detachment under Gnaeus Calvisius Sabinus sent by Caesar to Aetolia, and Scipio could only cause him to be pursued by his Thracian cavalry, for Calvinus threatened his reserve left behind under Favonius on the Haliacmon with the same fate which he had himself destined for Longinus. So Calvinus and Scipio met again on the Haliacmon, and encamped there for a considerable time opposite to each other.

Pompeius might choose among these plans; no choice was left to Caesar. After that unfortunate engagement he entered on his retreat to Apollonia. Pompeius followed. The march from Dyrrhachium to Apollonia along a difficult road crossed by several rivers was no easy task for a defeated army pursued by the enemy; but the dexterous leadership of their general and the indestructible marching energy of the soldiers compelled Pompeius after four days' pursuit to suspend it as useless.

He had now to decide between the Italian expedition and the march into the interior. However advisable and attractive the former might seem, and though various voices were raised in its favour, he preferred not to abandon the corps of Scipio, the more especially as he hoped by this march to get the corps of Calvinus into his hands. Calvinus lay at the moment on the Egnatian road at Heraclea Lyncestis, between Pompeius and Scipio, and, after Caesar had retreated to Apollonia, farther distant from the latter than from the great army of Pompeius; without knowledge, moreover, of the events at Dyrrhachium and of his hazardous position, since after the successes achieved at Dyrrhachium the whole country inclined to Pompeius and the messengers of Caesar were everywhere seized. It was not till the enemy's main force had approached within a few hours of him that Calvinus learned from the accounts of the enemy's advanced posts themselves the state of things. A quick departure in a southerly direction towards Thessaly withdrew him at the last moment from imminent destruction; Pompeius had to content himself with having liberated Scipio from his position of peril. Caesar had meanwhile arrived unmolested at Apollonia. Immediately after the disaster of Dyrrhachium he had resolved if possible to transfer the struggle from the coast away into the interior, with the view of getting beyond the reach of the enemy's fleet - the ultimate cause of the failure of his previous exertions. The march to Apollonia had only been intended to place his wounded in safety and to pay his soldiers there, where his depots were stationed; as soon as this was done, he set out for Thessaly, leaving behind garrisons in Apollonia, Oricum, and Lissus. The corps of Calvinus had also put itself in motion towards Thessaly; and Caesar could effect a junction with the reinforcements coming up from Italy, this time by the land-route through Illyria - two legions under Quintus Cornificius - still more easily in Thessaly than in Epirus. Ascending by difficult paths in the valley of the Aous and crossing the mountain-chain which separates Epirus from Thessaly, he arrived at the Peneius; Calvinus was likewise directed thither, and the junction of the two armies was thus accomplished by the shortest route and that which was least exposed to the enemy.

It took place at Aeginium not far from the source of the Peneius. The first Thessalian town before which the now united army appeared, Gomphi, closed its gates against it; it was quickly stormed and given up to pillage, and the other towns of Thessaly terrified by this example submitted, so soon as Caesar's legions merely appeared before the walls. Amidst these marches and conflicts, and with the help of the supplies - albeit not too ample - which the region on the Peneius afforded, the traces and recollections of the calamitous days through which they had passed gradually vanished.