Бану Каси
In the west, Mutarrif ibn Muhammad and his nephew Muhammad ibn Abd Allah struggled for dominance. The latter proved victorious, killing Mutarrif in 916. Since the death of Lubb in 907, the Banu Qasi had been left fractured and weakened in the face of two resurgent powers: to the north and west, a collaboration between the new king of León, Ordoño II, and Sancho I of Navarre brought a strong army south, ravaging the Banu Qasi lands around Viguera, Najera and Tudela in 918, while the young and energetic Abd ar-Rahman III, who was to temporarily reverse the centrifugal forces at work in the Emirate, soon to be Caliphate of Córdoba, sent armies north, routing the Christians. The next year, both Banu Qasi leaders, Muhammad ibn Abd Allah and Muhammad ibn Lubb, attacked the Banu al-Tawil at Barbastro, but Sancho took advantage of this, and allying himself with his cousin Bernard I of Ribagorza and the Banu al-Tawil, he attacked and burned Monzon, which was hence lost to the Banu Qasi. In 920, the emir, Abd ar-Rahman III, personally led the Cordoban army north, and forced Sancho to abandon fortifications he had been building. After some maneuvering the emir met the armies of Ordoño and Sancho, and defeated them at Valdejunquera. In 923, the Christian allies brought another force south, and while Muhammad ibn Abd Allah formed a coalition of local nobles to resist it, their armies were dispersed and Viguera and Najera fell. Like his father, Muhammad was captured, then assassinated on Sancho's orders, and when Abd ar-Rahman launched another punitive campaign the next year, on his return to Tudela he removed the Banu Qasi and sent them to Córdoba, placing their old rivals the Tujibids of Zaragoza in their place.