8th century A.D.), also called "Count Casius" (Spanish: Casio; Arabic: قَسِيّ قُومِس, "Qasīy Qūmis"), was a Hispano-Roman nobleman who founded the Banu Qasi dynasty.
[1] His actual existence has been contested on the grounds that embellishing stories related to Gothic ancestry were rather popular during the Caliphate of Cordoba.
[2] Historians point out that the origins of the Banu Qasi, as recounted by Ibn al-Qutiyya, could be a product of the spurious antiquarianism of the later Umayyad period rather than reliable genealogy, satisfying the need for stories which bridged the conquest.
The Banu Qasi dynasty descended from Fortun, the eldest son; the second son may have been the Abu Taur of Huesca who invited Charlemagne to Zaragoza in 778; and the Banu Salama, a family that ruled Huesca and Barbitanya (Barbastro) in the late tenth century, may have descended from Abu Salama.
[4] At the time of the Muslim arrival and after, Cassius ruled an area comprising Tudela, Tarazona, Borja and, probably, Ejea.