Zaida of Seville, c. 1070–1093/1107 (?), was a refugee Muslim princess, formerly associated with the Abbadid dynasty, who became a mistress and then perhaps wife of king Alfonso VI of Castile.^[1]

She is said by Al-Andalus sources to have been the daughter-in-law of Al Mutamid, the King of Seville, wife of his son Abu al Fatah al Ma'mun, ruler of the Muslim Taifa of Córdoba, (d. 1091).^{[2][3][4][5][6]} Later Iberian Christian chroniclers call her Al Mutamid's daughter, but the Islamic chronicles are considered more reliable.^[2][4][5][6] With the fall of Seville to the Almoravids, she fled to the protection of Alfonso VI of Castile, becoming his mistress, converting to Catholicism and taking the baptismal name of Isabel.^[2][4][5][6]

She was the mother of Alfonso's only son, Sancho,^[2][4][5][6] who, though illegitimate, was named his father's heir. (Sancho was killed at the Battle of Uclés (1108), during his father's lifetime.)

It has been suggested that Alfonso's fourth wife – also named Isabel – may have been Zaida,^[7][6][8][9] but this is still subject to scholarly debate. Some scholars believe Zaida and Queen Isabel were distinct,^[2][4][5] or suggest that Alfonso had two successive wives known as Isabel, with Zaida being the second.^[10] Alfonso's daughters Elvira and Sancha, were by Queen Isabel and Zaida may, therefore, have been their mother.^{[2][5][6][10]} Zaida is said to have died in childbirth, but it is unclear whether this was at the birth of her known son Sancho in 1093, or at the birth of a different child otherwise unknown. Queen Isabel is last mentioned in historical documents in May 1107,^[2] which coincide with the birth of the younger daughter of Queen Isabel (either Sancha or Elvira).^[2][5][6] A funerary marker, formerly at Sahagun but later moved to Leon, bore the inscription:

H.R. Regina Elisabeth, uxor regis Adefonsi, filia Benabet Regis Sevillae, quae prius Zayda, fuit vocata
("Queen Isabel, wife of King Alfonso, daughter of Aben-abeth, king of Seville; previously called Zayda.")

A second inscription memorializes Queen Isabel, making her daughter of Louis, King of France, although there was no French king named Louis in the generation prior to Queen Isabel. Neither memorial is contemporary and neither is generally viewed as credible.^[2][4][5][6]

• Alio, Jacqueline (2018). Queens of Sicily 1061–1266. New York: Trinacria.
• Canal Sánchez-Pagín, José María (1991). "Jimena Muñoz, Amiga de Alfonso VI". Anuario de Estudios Medievales. 21: 11–40. doi:10.3989/aem.1991.v21.1103.
• Fernándes-Montes y Corrales, Luis Miguel (2017). "La Mora Zaida o la Reina Isabel, ¿De Concubina a Reina". Antigua, Cápsula Histórica.
• Lévi-Provençal, Évariste (1934). "La 'Mora Zaida' femme d'Alfonse VI de Castile et leur fils l'Infant D. Sancho". Hesperis. 18: 1–8, 200–1.
• Martínez Díez, Gonzalo (2003). Alfonso VI: Señor del Cid, conquistador de Toledo.
• Montaner Frutos, Alberto (2005). "La Mora Zaida, entre historia y leyenda (con una reflexión sobre la técnica historiográfica alfonsí)". Historicist Essays on Hispano-Medieval Narrative: In Memory of Roger M. Walker. pp. 272–352.
• Palencia, Clemente (1988). "Historia y leyendas de las mujeres de Alfonso VI". Estudios sobre Alfonso VI y la reconquista de Toledo. pp. 281–90.
• Reilly, Bernard F. (1988). The Kingdom of León-Castilla under King Alfonso VI, 1065–1109. Princeton University Press.
• Reilly, Bernard F. (1995). The Contest of Christian and Muslim Spain, 1031–1157. Blackwell.
• Salazar y Acha, Jaime de (1992–1993). "Contribución al estudio del reinado de Alfonso VI de Castilla: algunas aclaraciones sobre su política matrimonial". Anales de la Real Academia Matritense de Heráldica y Genealogía. 2: 299–336.
• Salazar y Acha, Jaime de (2007). "De nuevo sobre la mora Zaida". Hidalguía: La Revista de Genealogía, Nobleza y Armas. 54: 225–242.