Mora. Parte de la Alianza entre Motamid y Alfonso. Ante la presion, se convierte y toma el nombre de Maria Isabel.

http://es.geocities.com/mundo_medieval/zaida.html

El rey castellano era muy mayor y tras cinco matrimonios y dos concubinatos (las relaciones incestuosas con su hermana Urraca merecen un aparte) no tuvo ningún hijo varón que le sucediera. Desde el mismo momento que nació Sancho Alfonsez el rey lo reconoció como su directo descendiente llamado a gobernar Castilla, León, Galicia con Portugal y el resto de condados.

http://freepages.genealogy.rootsweb.com/~jast/D0072/G0000023.html
Also remember that Alfonso VI was a king without a male heir. Even though he had the mistress Ximena/Jimena Munoz, she had only born him only daughters, Elvirs and Teresa. He also had a legitimate daughter, Urraca. So it was partly because of the very real threat of invasion by Arab Spain that Alfonso accepted Zaida as a mistress in 1092. She was the widow of Fath al-Mamun of Cordoba (who died in March of the previous year), daughter-in-law of al-Mutamid of Sevilla. . Importantly, Zaida became the mother of Alfonso's only son, Sancho, who would eventually be named his heir, in spite of his being illegitimate. Bishop Pelayo's chronicle (already quoted in the last post), states that she was baptized and given the Christian name Elizabeth (which was then equivalent to Isabel). . Zaida's monumental inscription states that she died on 13 [or 12, depending on the source] September in childbirth, but the year of her death does not survive. Thus the controversy. Levi-Provencal had concluded that she died during the birth of her son Sancho, on 12 September 1093. . But if you equate Zaida with Queen Elizabeth, who did not die until 1107, you arrive at a death date of 12/13 September 1107 (hence the varying dating given by different authorities). It is known that Queen Elizabeth was the mother of two daughters, and that Zaida was mother of Alfonso's only son. So if you equate the two women, it means she was mother of three children. But as she may not have died in 1093, the birth date of Zaida's son Sancho is problematic too. . There isn't enough surviving evidence to resolve these disputes. Different scholars interpret the evidence in different ways. BUT there is NO dispute that Teresa was Ximena's daughter, not a daughter of Zaida or Elizabeth

reedpcgen@@aol.com (Reedpcgen) posted to GEN-MEDIEVAL-L@@rootsweb.com on 15 Dec 1998 Subject: Re: Descent of Spanish Kings from Zaida: . "Christian Settipani was kind enough to bring to my attention a recent article by Jaime de Salazar y Acha, "Contribucion al estudio del reinado de Alfonso VI de Castilla: algunas aclaraciones sobre su politica matrimonal," Anales de la Real Academia Matritense de Heraldica y Genealogia, 2 (1992/3), pp. 299-343, sp. p. 323-8. . Though I have not seen this article, it is a long one, and if I understand correctly, he carefully examined all arguments for the different positions, both pro and con, and concludes without any hesitation that Zaida is Queen Isabel

1a esposa: Constanza
2a esposa: Berta
3a esposa: Zaida (Maria Isabel)
4a esposa: Elizabeth (Isabel, quizas la misma Zaida)
5a esposa: Beatriz

Ver con atencion la posibilidad de que Isabel (Elizabeth) y Zaida fueran la misma persona, en notas de dichas esposas.