With the exception of the maritime towns, which were defended by the Roman fleet, and the districts of the Indigetes and Laletani in the north-east corner of Spain, where Pompeius established himself after he had at length crossed the Pyrenees, and made his raw troops bivouac throughout the winter to inure them to hardships, the whole of Hither Spain had at the end of 677 become by treaty or force dependent on Sertorius, and the district on the upper and middle Ebro thenceforth continued the main stay of his power.

Even the apprehension, which the fresh Roman force and the celebrated name of the general excited in the army of the insurgents, had a salutary effect on it.

Marcus Perpenna, who hitherto as the equal of Sertorius in rank had claimed an independent command over the force which he had brought with him from Liguria, was, on the news of the arrival of Pompeius in Spain, compelled by his soldiers to place himself under the orders of his abler colleague.
For the campaign of 678 Sertorius again employed the corps of Hirtuleius against Metellus, while Perpenna with a strong army took up his position along the lower course of the Ebro to prevent Pompeius from crossing the river, if he should march, as was to be expected, in a southerly direction with the view of effecting a junction with Metellus, and along the coast for the sake of procuring supplies for his troops.

The corps of Gaius Herennius was destined to the immediate support of Perpenna; farther inland on the upper Ebro, Sertorius in person prosecuted meanwhile the subjugation of several districts friendly to Rome, and held himself at the same time ready to hasten according to circumstances to the aid of Perpenna or Hirtuleius.

It was still his intention to avoid any pitched battle, and to annoy the enemy by petty conflicts and cutting off supplies.
Pompeius Defeated Pompeius, however, forced the passage of the Ebro against Perpenna and took up a position on the river Pallantias, near Saguntum, whence, as we have already said, the Sertorians maintained their communications with Italy and the east.