After arriving at the fortified city of Ategua, Caesar began besieging it, building several camps around it. Gnaeus and Labienus marched their army around Caesar's positions, hoping to surprise him by coming in from an unexpected direction. They approached under the cover of a thick fog, surprising a number of Caesar's pickets. When the fog lifted, it became clear Caesar had taken all the highground around the city and was entrenched very well. Building a camp to the west (between Caesar and Ucubi), they tried to come up with a plan to dislodge their opponent from his superior position. They launched an attack on the camp of Postumius and the XXVIII, but were repulsed when Caesar sent the V, VI and X to aid their comrades. The following day Caesar was reinforced by his allies, most notably king Bogud of West-Mauretania. Under Labienus’ advice, Gnaeus Pompeius decided to avoid an open battle, and Caesar was forced to wage a winter campaign, while procuring food and shelter for his army. In early 45 BC, the pro-Caesarian faction in Ategua offered to surrender the city to Caesar, but when the Pompeian garrison found out, they executed the pro-Caesarian leaders. The garrison tried to fight their way through Caesar's lines some time after the incident, but were beaten back. The city surrendered soon after; this was an important blow to the Pompeian confidence and morale, and some of the native allies started to desert to Caesar.
