It thus remained possible for Caesar, notwithstanding the intervention of the Spanish war, to assume the offensive also in Macedonia; and he at least was not slow to act. He had long ago ordered the collection of vessels of war and transports in Brundisium, and after the capitulation of the Spanish army and the fall of Massilia had directed the greater portion of the select troops employed there to proceed to that destination. The unparalleled exertions no doubt, which were thus required by Caesar from his soldiers, thinned the ranks more than their conflicts had done and the mutiny of one of the four oldest legions, the ninth on its march through Placentia was a dangerous indication of the temper prevailing in the army; but Caesar's presence of mind and personal authority gained the mastery, and from this quarter nothing impeded the embarkation. But the want of ships, through which the pursuit of Pompeius had failed in March 705, threatened also to frustrate this expedition. The war-vessels, which Caesar had given orders to build in the Gallic, Sicilian, and Italian ports, were not yet ready or at any rate not on the spot; his squadron in the Adriatic had been in the previous year destroyed at Curicta[27]; he found at Brundisium not more than twelve ships of war and scarcely transports enough to convey over at once the third part of his army - of twelve legions and 10,000 cavalry - destined for Greece. The considerable fleet of the enemy exclusively commanded the Adriatic and especially all the harbours of the mainland and islands on its eastern coast. Under such circumstances the question presents itself, why Caesar did not instead of the maritime route choose the land route through Illyria, which relieved him from all the perils threatened by the fleet and besides was shorter for his troops, who mostly came from Gaul, than the route by Brundisium. It is true that the regions of Illyria were rugged and poor beyond description; but they were traversed by other armies not long afterwards, and this obstacle can hardly have appeared insurmountable to the conqueror of Gaul.

Perhaps he apprehended that during the troublesome march through Illyria Pompeius might convey his whole force over the Adriatic, whereby their parts might come at once to be changed - with Caesar in Macedonia, and Pompeius in Italy; although such a rapid change was scarcely to be expected from his slow-moving antagonist. Perhaps Caesar had decided for the maritime route on the supposition that his fleet would meanwhile be brought into a condition to command respect, and, when after his return from Spain he became aware of the true state of things in the Adriatic, it might be too late to change the plan of campaign. Perhaps - and, in accordance with Caesar's quick temperament always urging him to decision, we may even say in all probability - he found himself irresistibly tempted by the circumstance that the Epirot coast was still at the moment unoccupied but would certainly be covered in a few days by the enemy, to thwart once more by a bold stroke the whole plan of his antagonist.

However this may be, on the 4th Jan. 706[28] Caesar set sail with six legions greatly thinned by toil and sickness and 600 horsemen from Brundisium for the coast of Epirus. It was a counterpart to the foolhardy Britannic expedition; but at least the first throw was fortunate. The coast was reached in the middle of the Acroceraunian (Chimara) cliffs, at the little-frequented roadstead of Paleassa (Paljassa). The transports were seen both from the harbour of Oricum (creek of Avlona) where a Pompeian squadron of eighteen sail was lying, and from the headquarters of the hostile fleet at Corcyra; but in the one quarter they deemed themselves too weak, in the other they were not ready to sail, so that the first freight was landed without hindrance. While the vessels at once returned to bring over the second, Caesar on that same evening scaled the Acroceraunian mountains. His first successes were as great as the surprise of his enemies. The Epirot militia nowhere offered resistance; the important seaport towns of Oricum and Apollonia along with a number of smaller townships were taken, and Dyrrhachium, selected by the Pompeians as their chief arsenal and filled with stores of all sorts, but only feebly garrisoned, was in the utmost danger.

But the further course of the campaign did not correspond to this brilliant beginning. Bibulus subsequently made up in some measure for the negligence, of which he had allowed himself to be guilty, by redoubling his exertions. He not only captured nearly thirty of the transports returning home, and caused them with every living thing on board to be burnt, but he also established along the whole district of coast occupied by Caesar, from the island Sason (Saseno) as far as the ports of Corcyra, a most careful watch, however troublesome it was rendered by the inclement season of the year and the necessity of bringing everything necessary for the guard-ships, even wood and water, from Corcyra; in fact his successor Libo - for he himself soon succumbed to the unwonted fatigues - even blockaded for a time the port of Brundisium, till the want of water again dislodged him from the little island in front of it on which he had established himself. It was not possible for Caesar's officers to convey the second portion of the army over to their general. As little did he himself succeed in the capture of Dyrrhachium. Pompeius learned through one of Caesar's peace envoys as to his preparations for the voyage to the Epirot coast, and, thereupon accelerating his march, threw himself just at the right time into that important arsenal.

The situation of Caesar was critical. Although he extended his range in Epirus as far as with his slight strength was at all possible, the subsistence of his army remained difficult and precarious, while the enemy, in possession of the magazines of Dyrrhachium and masters of the sea, had abundance of everything. With his army presumably little above 20,000 strong he could not offer battle to that of Pompeius at least twice as numerous, but had to deem himself fortunate that Pompeius went methodically to work and, instead of immediately forcing a battle, took up his winter quarters between Dyrrhachium and Apollonia on the right bank of the Apsus, facing Caesar on the left, in order that after the arrival of the legions from Pergamus in the spring he might annihilate the enemy with an irresistibly superior force. Thus months passed.

If the arrival of the better season, which brought to the enemy a strong additional force and the free use of his fleet, found Caesar still in the same position, he was to all appearance lost, with his weak band wedged in among the rocks of Epirus between the immense fleet and the three times superior land army of the enemy; and already the winter was drawing to a close. His sole hope still depended on the transport fleet; that it should steal or fight its way through the blockade was hardly to be hoped for; but after the first voluntary foolhardiness this second venture was enjoined by necessity. How desperate his situation appeared to Caesar himself, is shown by his resolution - when the fleet still came not - to sail alone in a fisherman's boat across the Adriatic to Brundisium in order to fetch it; which, in reality, was only abandoned because no mariner was found to undertake the daring voyage.