Battle of Roncevaux Pass (824)

After Louis the Pious' half-hearted expedition to Pamplona circa 814, Basque tribal chieftain Enneko Aritza, who held strong family ties with the Banu Qasi led by his half-brother Musa, prevailed in the fortress circa 816 (or earlier) after news of Charlemagne's death (814) spread and a Frankish vassal, Belasko of Pamplona— Velasco, cited as Balashk al-Yalashki in Muslim sources—was defeated in the Battle of Pancorbo.

All Vasconia remained at this point in a shaky state of rebellion and the Frankish tenure on the Hispanic Marches was shifting out of control.

According to Umayyad chroniclers, a joint force of Navarrese (Enneko Aritza), Aragonese and Banu Qasi warriors, hidden in the forests, awaited the Carolingian army on the sinuous narrow passes of the region of Cize.

While the Frankish count Aeblus was sent prisoner to Córdoba, Aznar Sánchez was released thanks to his kinship with the captors ("Asinarius vero misericordia eorum, qui eum ceperant, quasi qui consanguineus eorum esset") a fact that evidenced the good relations entertained at that moment by the joint Banu Qasi - Arista tandem with the Cordovan Umayyad, maybe after the accession to the throne of Abd ar-Rahman II in 822.

The new independent Basque kingdom brought about the definite detachment of the territories south of the Pyrenées from the Duchy of Vasconia suzerain to the Franks, as well as the loss of control over the Hispanic Marches for them and the start of an on-off alliance between the kings of Pamplona and the muwallad Banu Qasi.