The Banu Qasi emirate and its rival, the Kingdom of Pamplona, in the 10th century
|Languages||Andalusi Arabic(official), Mozarabic, Ladino, Basque|
The Banu Qasi, Banu Kasi, Beni Casi (Arabic: بنو قسي or بني قسي, meaning "sons" or "heirs of Cassius") or Banu Musa were a Basque Muladi dynasty that ruled the upper Ebro valley in the 9th century, before being displaced in the first quarter of the 10th century.
The family is said to descend from the Hispano-Roman or Visigothic nobleman named Cassius.  According to the 10th century Muwallad historian Ibn al-Qutiyya, Count Cassius converted to Islam in 714 as the mawali (client) of the Umayyads, shortly after the Umayyad 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 Navarra) formed a semi-autonomous principality. The tiny Basque 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. The Banu Qasi were a local, rather than a foreign-imposed, Muslim regime, and while nominally clients of the caliphate, they continually shifted alliances among the Basques of Pamplona, Aragon and Ribagorza to the north, other muladi dynasties of the Ebro Valley, and the Umayyads to the south over the next two centuries. Though Muslim, they frequently intermarried with the Christian Basque nobility. Musa ibn Musa and Pamplona king Íñigo Arista were maternal half-brothers, while Musa also married Arista's daughter, and married a daughter and nieces to other Basque princes. The cultural ambivalence of the Banu Qasi is also demonstrated by their mixed use of names: for example, Arabic (Muhammad, Musa, Abd Allah), Latinate (Auria, Lubb), and Basque (Garsiya).
The Umayyads of Córdoba sanctioned the rule of the Banu Qasi and repeatedly granted them autonomy by appointing them as governors, only to replace them as they expressed too much independence, or launch punitive military expeditions into the region. Such acts on the part of the Umayyads demonstrated their failure to ever fully resolve the problem of effective, central control of outlying regions.
First rise to prominence
The speculated homeland of Count Cassius was a narrow strip across the Ebro from Tudela. The Arab historian Ibn Hazm listed the sons of Count Cassius as Fortun, Abu Tawr, Abu Salama, Yunus and Yahya. Of these, it has been suggested that the second may be the Abu Taur, Wali of Huesca, who invited Charlemagne to Zaragoza in 778. Likewise, the Banu Salama, removed from power in Huesca and Barbitanya (Barbastro) at the end of the 8th century, may have derived from Abu Salama. Subsequent leaders of the family descend from the eldest son, Fortun. His son, Musa ibn Fortun ibn Qasi, first garnered notice in 788, when on behalf of emir Hisham I of Córdoba he put down the rebellion of the Banu Husain in Zaragoza. The fate of Musa ibn Fortun is debated. An account of the 788 rebellion tells of Musa's murder shortly thereafter at the hands of a Banu Husain follower, yet a "Fortun ibn Musa" is said to have been killed in his own 802 Zaragoza uprising, and it has been suggested that this name may be an error for Musa ibn Fortun. However, Ibn Hayyan also reports a Fortun of the Banu Qasi forming a coalition of the Christians of Pamplona, Álava, Castile, Amaya and Cerdaña to fight Amrus ibn Yusuf at this time, suggesting that this is instead a son of Musa ibn Fortun overlooked by ibn Hazm, whose genealogy provides most of what we know about the clan. In the next generation, Mutarrif ibn Musa, assassinated in Pamplona in 798 by pro-Frankish interests, was likely a son of Musa ibn Fortun. It was Musa's son Musa ibn Musa ibn Qasi whose rule brought the family to the peak of its power.
Musa ibn Musa
While Musa had been orphaned at an early age, his military activity may have begun in the 820s, including probable participation in the third Battle of Roncevaux. Historians agree that in the 840s, Musa launched a series of revolts, in conjunction with his maternal half-brother, Íñigo Arista of Pamplona. Abd ar-Rahman II defeated them, and took Musa's son Lubb hostage. Musa repeatedly submitted, only to rise again. After repeated rebellions he controlled a region along the Ebro from Borja to Logroño, including Tudela, Tarazona, Arnedo and Calahorra. The 851/2 deaths of Íñigo Arista and Abd er-Rahman II, as well as a victory over Christian forces at Albelda, gave Musa unprecedented status. The new emir, Muhammad I of Córdoba named Musa the Wali of Zaragoza and governor of the Upper March. Over the next decade Musa expanded the family's lands to include Zaragoza, Najera, Viguera and Calatayud, while also governing Tudela, Huesca and Toledo, leading a Christian chronicler to call him "The Third King of Spain".
However in 859, Ordoño I of Asturias and García Íñiguez of Pamplona joined forces to deal Musa a crushing defeat at Albelda, which passed into Christian legend as the Battle of Clavijo. Emir Muhammad then stripped Musa of his titles and restored direct Cordoban control over the region. Musa died in 862 of wounds received in a petty squabble with a son-in-law, and the family disappeared from the political scene for a decade.
Sons of Musa
Following the 862 death of Musa, nothing is known of the family until 871. It is presumed that the members of the family associated with the Cordoban court and military campaigns, but no record of their presence there survives. Alternatively, it has been suggested that during this period, son Lubb ibn Musa ibn Qasi developed his friendly relations with Asturian king Ordoño. By the time the Banu Qasi reappear, they had lost control of most of their lands, being left with just a small area surrounding Arnedo. In 870, a rebellion in Huesca initiated a chain of events that would bring the Banu Qasi back to dominance. In that year, Amrus ibn Umar of the Banu Amrus assassinated the amil Musa ibn Galindo, son of the turncoat brother of Pamplona king García Íñiguez. The emir, Muhammad, sent an army north, but Amrus allied himself with García, and the Cordoban general, Abd al-Gafir ibn Abd al-Aziz, was killed before the gates of Zaragoza. The Banu Qasi sons of Musa, apparently under the leadership of eldest son Lubb ibn Musa, then allied themselves with García, and reestablished control over their father's possessions. First, the residents of Huesca called on Mutarrif ibn Musa ibn Qasi for leadership. In January 872, Isma‘il ibn Musa entered Zaragoza, and was there joined by Lubb, the two of them together taking Monzon. Isma‘il also allied himself with the Banu Jalaf of Barbitanya, marrying Sayyida, daughter of Abd Allah ibn Jalaf. Fortun ibn Musa occupied Tudela, whose governor the Banu Qasi imprisoned at Arnedo, then killed following an escape. Lubb also occupied and refortified Viguera.
The immediate response of emir Muhammad was to try to limit the expansion of the Banu Qasi by installing a rival dynasty, the Arab Banu Tujibi, in Calatayud, the one part of their father's possessions not reclaimed. In the next year, 873, Muhammad launched a campaign against the various northern rebels. He first bought off the rebels of Toledo with governorships, and this encouraged Amrus to offer his loyalty, for which he was rewarded with Huesca where he captured Mutarrif and his family, including wife Belasquita, the daughter of García Íñiguez of Pamplona. In spite of a desperate attack by the combined troops of his brothers, Mutarrif and three sons, Muhammad, Musa and Lubb, were taken to Córdoba and crucified. The next year, Fortun died in Tudela, while Lubb was killed in an accident in Viguera in 875. This left control of the family in the hands of two men, the remaining brother Isma‘il ibn Musa in Monzon, and Lubb's son, Muhammad ibn Lubb ibn Qasi, who is first known as a defender of Zaragoza against the emirate troops.
Muhammad ibn Lubb
Over the next decade, following the deaths of his father and two uncles, Muhammad ibn Lubb ibn Qasi maneuvered to become the leader of the family. He resisted 879 and 882 campaigns from Córdoba. The latter was under general, Hashim ibn Abd al-Aziz, and Muhammad tried to persuade Hashim to unite with him against the Asturians, now ruled by Alfonso III. Earlier hostage taking by all parties greatly complicated the situation. Hashim did not want to antagonize Alfonso who was holding his son. Hashim himself held Isma‘il, the son of Muhammad ibn Lubb, and he sent his captive and other gifts to Alfonso in return for his son. Muhammad would later ally himself with the kings of Pamplona and Asturias, and it was apparently he who raised the future Ordoño II of León at his court. The struggle for power within the Banu Qasi family came to a head in 882, when Muhammad fought, near Calahorra, a 7000-man force of his uncle Isma‘il ibn Musa, and Isma‘il ibn Fortun, a son of his uncle Fortun. In the following internecine squabbles, Fortun's four sons were killed and Isma‘il ibn Musa was forced to retire to Monzon. From there he rebuilt Lleida and routed an army sent by Wilfred of Barcelona. Muhammad ibn Lubb, now the clear head of the family, was left in control of the majority of the Banu Qasi lands. In 884, the emir sent two military campaigns into the region and took Zaragoza, although chronicler ibn Hayyan reports that Muhammad ibn Lubb had sold the city to count Raymond I of Pallars and Ribagorza prior to its fall. This resulted in a consolidated Banu Qasi powerbase around Arnedo, Borja, Calahorra and Viguera, with Isma‘il holding an enclave to the east, around Monzon and Lleida.
In 885 and 886, Muhammad launched attacks against Castile, in the first apparently killing count Diego Rodríguez Porcelos, while the second was an attack on Álava in which many Christians were killed. The latter year also saw the death of emir Muhammad I of Córdoba. Muhammad ibn Lubb tested his power against the new emirs, and they responded by again trying to balance Banu Qasi power in the region, giving Zaragoza to the rival Tujibids, and Huesca to Muhammad ibn Abd al-Malik al-Tawil of the Muladi Banu Shabrit clan. The latter was shortly challenged by Isma‘il ibn Musa, whose sons fought a battle with al-Tawil's troops, Musa ibn Isma‘il being killed and his brother Mutarrif captured. Isma‘il died shortly thereafter, in 889, and al-Tawil and Muhammad ibn Lubb each took their case to emir Abd Allah for possession of Isma‘il's lands, the emir confirming the succession of Muhammad ibn Lubb. There followed a period of relative peace and collaboration between Muhammad ibn Lubb and al-Tawil. In 891, Muhammad defeated a Christian force at Castro Sibiriano, but he dedicated most of his efforts in his final years against Tujibid Zaragoza, initiating what would become a 17-year siege. In 897, the citizens of Toledo rose up and offered their city to Muhammad, but being occupied with Zaragoza, he sent his son Lubb. Muhammad was reconnoitering Zaragoza in 898, when on 8 October, he was caught by a guard who spitted him on a lance. His head was presented to the Tujibids, who sent it to Córdoba, where it was displayed in front of the palace for eight days before being buried with the honors due a brave foe.
Lubb ibn Muhammad
Muhammad's son, Lubb ibn Muhammad ibn Qasi, was born in 870, and was already active at the time of his father's death. In 896, he was refortifying Monzon when al-Tawil of Huesca tried his luck. Though being attacked by a larger, better equipped army, Lubb was able to rout al-Tawil's men, taking his brother prisoner. In January 897 he went to Toledo to take up the leadership offer the citizens had made his father. Back in the east, he launched an attack on Aura that led to the death of Wilfred of Barcelona. Returning through Toledo in 898, he next marched to Jaén, with the intent of forming a coalition with another rebel, Umar ibn Hafsun, but before Umar reached Jaén, the news of his father's death at Zaragoza forced Lubb's return to Tudela, where he formally recognized the sovereignty of the emir, Abd Allah, in exchange for the formal governorship over Tudela and Tarazona. His return north found al-Tawil moving to take advantage of the temporary power vacuum and three weeks after his father's death, Lubb captured the Huesca ruler in a skirmish. To buy his freedom, al-Tawil ceded lands between Huesca and Monzon to Lubb, and agreed to pay 100,000 gold dinares for the possession of Huesca. Paying 50,000 immediately, he gave his son Abd al-Malik and daughter Sayyida as hostages to ensure payment of the second half. Lubb would relent, forgiving the remaining debt and returning the hostages except Sayyida, who he married.
Lubb ibn Muhammad continued his father's siege of Zaragoza, but found himself drawn in other directions. Perhaps in 900, Alfonso III, in conjunction with Fortún Garcés of Pamplona, launched a raid against Tarazona, in Lubb's realm, which he successfully blocked. Then in 903, Toledo again rebelled against Córdoba, asking Lubb to take control. He sent his brother Mutarrif, who was proclaimed their lord. Mutarrif's fate is unknown, but by 906, he had been replaced by Lubb's kinsman Muhammed ibn Isma‘il, son of Isma‘il ibn Musa, who was then assassinated. Alfonso again attacked Lubb's lands, laying siege to Grañón, but was forced to lift the siege when Lubb moved with an army toward Alava. This threat neutralized, Lubb turned toward Pallars, ravaging the lands, killing hundreds and taking a thousand captives, including Isarno, Count Raymond's son, who was kept in Tudela for a decade before being freed.
In 905, a coalition of the King of Asturias, the counts of Aragon and Pallars, and, it is sometimes claimed, Lubb ibn Muhammad, engineered a coup in Navarre that brought Sancho Garcés to the throne in place of Fortún Garcés. Two years later, Lubb launched an attack on Pamplona and fought at "Liédena" on 30 September 907, resulting in a total rout of the Banu Qasi forces, while Lubb was killed. The transcendent battle marked a permanent change in the regional balance, Sancho's Pamplona becoming a major regional power, while it initiated the final decline of the Banu Qasi.
Decline and extermination
With the fall of Lubb, his local rivals immediately fell upon the Banu Qasi lands. Sancho descended toward Calahorra. The Tujibids finally broke the siege of Zaragoza and captured Ejea. Al-Tawil retook the lands he had lost, and proceeded to overrun the family's eastern enclave, taking Barbastro and Lleida. Monzon was briefly controlled by Lubb's brother Yunis ibn Muhammad, but he could not hold it, and Monzon too fell to the al-Tawil. In the reduced western lands, Lubb was succeeded by brother Abd Allah ibn Muhammad ibn Qasi. In 911, Abd Allah and al-Tawil jointly, along with al-Tawil's brother-in-law Galindo Aznárez II of Aragon, attacked Pamplona. After destroying several castles, they developed cold feet and withdrew, but were caught by Sancho. Al-Tawil defected and escaped, while Galindo was crushed and forced to recognize Sancho as feudal sovereign, ending the autonomy of the Aragon. Arab sources describe Abd Allah's rear-guard action at Luesia as a victory, but if so it was only a tactical victory and he immediately retreated south. In 914, Sancho turned the tables, marching into the heart of the Banu Qasi homeland, taking Arnedo and attacking Calahorra. In the next year, 915, Sancho turned toward Tudela, and there captured Abd Allah, killing a thousand of his best men. Mutarrif ibn Muhammad ibn Qasi, Abd Allah's brother, rushed to relieve the city, and Abd Allah was ransomed, his daughter Urraca and probably son Fortun ibn Abd Allah being given as hostages. However, two months later Abd Allah was assassinated, it is said, through the machinations of Sancho.
The only bright spot for the family in this period happened in the east. In 913, Muhammad ibn Abd al-Malik al-Tawil died, and the next year, the residents of Monzon rejected his son Amrus ibn Muhammad, and invited the Banu Qasi to return in the person of Muhammad ibn Lubb, son of Lubb ibn Muhammad. After a brief siege, he was able to reclaim the city for his family, as well as Lleida.
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 the two Banu Qasi leaders, Muhammad ibn Abd Allah and Muhammads ibn Lubb, attacked the Banu al-Tawil at Barbastro, but Sancho took advantage of this, and allying himself with his cousin Bernard 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. After 923, only the eastern enclave encompassing Lleida and the castles of Balaguer, Barbastro and Ayera were in the hands of the family. However, one by one these expelled Muhammad ibn Lubb ibn Qasi and turned to the Tujibids for leadership, leaving him only Ayera in 928, when Jimeno Garcés, the new king of Navarre, intervened on his behalf in opposition to Hasim ibn Muhammad al-Tujibi. The next year, Muhammad fell victim to an ambush and was killed by his brother-in-law "Raymond of Pallars".
The death of Muhammad ibn Lubb marked the end of the Banu Qasi in the Ebro valley. Their rivals the Tujibids would follow their model, making an independent peace with Leon in 937, a move that resulted in a punitive expedition from the Caliph similar to those of prior years against the Banu Qasi. The Tujibids would eventually establish a full-fledged Taifa kingdom centered at Zaragoza. Two other Taifa crowns were ruled by men with names reminiscent of the Banu Qasi and are claimed as dynastic members, although the precise connection, if any, is unknown. A small Taifa state at Alpuente was founded by Abd Allah ibn Qasim. He was of a convert family that claimed a tribal affiliation with the Yamanī/Fíhrī. In 1144, another Christian convert and Sufi mystic from Silves, Abu-l-Qasim Ahmad ibn al-Husayn ibn Qasi, called ibn Qasi, rose and extablished a Taifa state at Mértola, expanding it to much of southern Portugal, and he encouraged the successful move of the Almohads (to whom he would submit) against Seville. They fell out and ibn Qasi was assassinated in 1151 by his own men. Fortún Ochoiz, a Navarrese who ruled La Rioja in the first half of the eleventh century, may be a descendant of the Banu Qasi.
Leadership of the Banu Qasi
The following men are the documented leaders of the Banu Qasi (entried in italics are of uncertain affiliation to the family):
- Cassius, fl. 714
- Abu Taur, Wali of Huesca, fl. 778, perhaps son of Cassius
- Musa ibn Fortun, (perh. assassinated 788), grandson of Cassius
- Mutarrif ibn Musa, assassinated 799, perhaps son of Musa ibn Fortun
- Fortun ibn Musa, killed in rebellion 801, perhaps son of Musa ibn Fortun, else identical to him
- Musa ibn Musa, d. 862, son of Musa ibn Fortun
- Lubb ibn Musa, d. 875, son of Musa ibn Musa
- Isma‘il ibn Musa, co-leader to 882, d. 889, son of Musa ibn Musa
- Muhammad ibn Lubb, co-leader to 882, then sole leader, d. 899, son of Lubb ibn Musa
- Lubb ibn Muhammad, d. 907, son of Muhammad ibn Lubb
- Abd Allah ibn Muhammad, d. 915, son of Muhammad ibn Lubb
- (succession struggle between Mutarrif ibn Muhammad and Muhammad ibn Abd Allah, 915-916)
- Muhammad ibn Abd Allah, d. 923, son of Abd Allah ibn Muhammad
- Muhammad ibn Lubb, d. 929, son of Lubb ibn Muhammad
- (end of dynasty)
- Warwick Ball (2009). Out of Arabia: Phoenicians, Arabs, and the discovery of Europe. East & West Publishing. pp. 117–122. ISBN 978-1-907318-00-9. Retrieved 30 March 2013.
- Cañada Juste, "Los Banu Qasi", 6; This origin legend, as recounted by Ibn al-Qutiyya, may be a product of the spurious antiquarianism of the latter Umayyad period that satisfied the need for stories which bridged the conquest, rather than reliable genealogy.
- Cañada Juste, "Los Banu Qasi", 12
- Cañada Juste, "Los Banu Qasi", 7-9
- This is as the pedigree appears in the work of Ibn Hazm, but historian Al-Udri refers to his descendant as Muhammad ibn Lubb ibn Muhammad ibn Lubb ibn Musa ibn Musa ibn Fortun ibn Garsiya (Muhammad son of Lubb, son of . . . son of Musa, son of Fortun, son of Garsiya). This last patronymic may simply be an error for ibn Qasi (son of Cassius), or may suggest that Ibn Hazm has dropped a generation, Garcia, between Cassius and Fortun in his account of the senior line. An additional generation would better fit the chronology. de la Granja, "La Marca Superior", pp. 519-520
- He is frequently said[who?] to have been governor of the city, but this does not appear in the primary source.
- Cañada Juste, "Los Banu Qasi", 8-12. Martínez Díez attempts to harmonize the difficulties with the pedigree though the insertion of two generations, making a first Musa ibn Fortun, murdered 788 the father of Mutarrif ibn Musa of 798 and Fortun ibn Musa of 802, in turn father of an otherwise undocumented Musa ibn Fortun, father of Musa ibn Musa.
- Cañada Juste, "Los Banu Qasi", 12-41
- Cañada Juste, "Los Banu Qasi", 41-44
- Cañada Juste, "Los Banu Qasi", 42-43
- Cañada Juste, "Los Banu Qasi", 43-45; de la Granja, "La Marca Superior", pp. 474, 514
- Cañada Juste, "Los Banu Qasi", 45-48; Two of Mutarrif's remaining sons, ‘Abd Allah and Isma‘il, converted to Christianity and fled north.
- Cañada Juste, "Los Banu Qasi", 48-50
- Cañada Juste, "Los Banu Qasi", 54-56
- Cañada Juste, "Los Banu Qasi", 57
- Cañada Juste, "Los Banu Qasi", 56-58
- Cañada Juste, "Los Banu Qasi", 59
- Cañada Juste, "Los Banu Qasi", 51-2, 58-60
- Cañada Juste, "Los Banu Qasi", 59-63
- Cañada Juste, "Los Banu Qasi", 63-64
- Cañada Juste, "Los Banu Qasi", 66
- Cañada Juste, "Los Banu Qasi", 64-5
- Cañada Juste, "Los Banu Qasi", 66-67
- Cañada Juste, "Los Banu Qasi", 67-68
- Cañada Juste, "Los Banu Qasi", 67
- Cañada Juste, "Los Banu Qasi", 67-70
- Cañada Juste, "Los Banu Qasi", 71; Lubb thus also linked himself with the Galindo Aznar, Count of Aragon, whose sister was the girl's mother.
- Cañada Juste, "Los Banu Qasi", 71-72
- Cañada Juste, "Los Banu Qasi", 72-73; His son Lubb ibn Muhammad ibn Is'mael ibn Qasi fled to join the Fatimids, taking the Banu Qasi line into Africa.
- Cañada Juste, "Los Banu Qasi", 73
- Cañada Juste, "Los Banu Qasi", 74-75
- Cañada Juste, "Los Banu Qasi", 77
- Cañada Juste, "Los Banu Qasi", 77-79
- Cañada Juste, "Los Banu Qasi", 79-80
- Cañada Juste, "Los Banu Qasi", 80
- Both would later convert, Urraca marrying Fruela II of León. Cañada Juste, "Los Banu Qasi", 81,91
- Cañada Juste, "Los Banu Qasi", 81
- Cañada Juste, "Los Banu Qasi", 80-81
- Cañada Juste, "Los Banu Qasi", 83
- Cañada Juste, "Los Banu Qasi", 85
- Cañada Juste, "Los Banu Qasi", 85-86
- Cañada Juste, "Los Banu Qasi", 86
- Cañada Juste, "Los Banu Qasi", 88-89
- Cañada Juste, "Los Banu Qasi", 89-90; de la Granja, "La Marca Superior", p. 486
- Cañada Juste, "Los Banu Qasi", 90. His exact identity is subject to speculation, there being no Raymond in this generation of the Pallars/Ribagorza ruling family, and perhaps ibn Raymond – i.e. one of the sons of count Raymond I of Pallars and Ribagorza, is intended.
- Richard A. Fletcher, The Quest for El Cid, Oxford University Press US, 1991, p. 29; William Montgomery Watt and Pierre Cachia, A History of Islamic Spain, Edinburgh University Press, 1996, p. 40
- Brian A. Catlos, The Victors and the Vanquished, Cambridge University Press, 2004, p. 40n.
- Richard Fletcher, Moorish Spain, University of California Press, 2006, p. 121; Hugh N. Kennedy, Muslim Spain and Portugal: A Political History of Al-Andalus, Longman, 1996, p. 191; Bernard F. Reilly, The Kingdom of León-Castilla Under King Alfonso VII, 1126-1157, University of Pennsylvania Press, 1998, p. 84; Joseph F. O'Callaghan, A History of Medieval Spain, Cornell University Press, 1983, pp. 228-9.
- Alberto Cañada Juste, "El posible solar originario de los Banu Qasi", in Homenaje a don José M.ª Lacarra..., Zaragoza, 1977, I.
- Alberto Cañada Juste, "Los Banu Qasi (714-924)", in Principe de Viana, vol. 41, pp. 5–95 (1980).
- Fernando de la Granja, "La Marca Superior en la Obra de al-'Udrí", Estudios de la Edad Media de la Corona de Aragón, vol. 8 (1967), pp. 457–545
- Gonzalo Martínez Díez. El condado de Castilla (711-1038): la historia frente a la leyenda. Marcial Pons Historia, 2005. vol. 1, p. 141.
- Rosamond McKitterick, et al., The New Cambridge Medieval History.Cambridge University Press, 2005. ISBN 0-521-36292-X
- Joseph F. O'Callaghan, A History of Medieval Spain. Cornell University Press, 1983. ISBN 0-8014-9264-5
- Banu Kasi, Casius, Kasi and Qasi in the Spanish-language Auñamendi Encyclopedia.
- Historia Medieval del Reyno de Navarra; Banu Qasi