The Banu Qasi, Banu Kasi, Beni Casi (, meaning "sons" or "heirs of Cassius"), Banu Musa, or al-Qasawi were a Muladí (local convert) dynasty that in the 9th century ruled the Upper March, a frontier territory of the Umayyad Emirate of Córdoba, located on the upper Ebro Valley. At their height in the 850s, family head Musa ibn Musa al-Qasawi was so powerful and autonomous that he would be called 'The Third Monarch of Hispania'. In the first half of the 10th century, an intra-family succession squabble, rebellions and rivalries with competing families, in the face of vigorous monarchs to the north and south, led to the sequential loss of all of their land. Dynastic beginnings The family is said to descend from the Hispano-Roman or Visigothic nobleman named Cassius. Muslim chronicles and the Chronicle of Alfonso III suggest he was a Visigoth. According to the 10th century Muwallad historian, Ibn al-Qūṭiyya, Count Cassius converted to Islam in 714 as the mawlā (client) of the Umayyads, shortly after their conquest of Hispania. After his conversion, he is said to have traveled to Damascus to personally swear allegiance to the Umayyad Caliph, Al-Walid I. Under the Banu Qasi, the region of Upper Ebro (modern districts of Logroño and southern Navarre, based in Tudela) formed a semi-autonomous principality. The tiny emirate was faced by enemies in several directions. Although never realized, the threat of Frankish attempts to regain control over the western Pyrenees was a real one. In actuality, even more menacing was the gradual eastwards expansion of the Asturian Kingdom; while in the south lay the Caliphate of Córdoba, ever anxious to impose its authority over the frontier regions. As a local Muslim dynasty in the Ebro valley (the Upper March of Al-Andalus; , Aṯ-Ṯaḡr al-Aʿlà), the Banu Qasi were nominally clients of the emirate, but they thrived on regional rivalries and alliances with other Muwallad dynasties of the Upper March, the Vascon tribal chieftains of Pamplona and Aragon, as well as with the Catalan counts of Pallars-Ribagorza to the north and Barcelona to the east, the Kingdom of Asturias to the west and the Umayyads to the south over the next two centuries. They frequently intermarried with other regional nobility, both Muslim and Christian. Musa ibn Musa and the Pamplona king Íñigo Arista were maternal half-brothers, while Musa also married Arista's daughter, and his own daughter and nieces were married