Sancho Alfónsez

Sancho Alfónsez (or Adefónsez) (ca. 1093 – 29 May 1108) was the only son of Alfonso VI of Castile and León and the Moorish princess Zaida. Alfonso's heir from May 1107, he eventually co-ruled from Toledo. He predeceased his father, being killed while trying to escape the field of the Battle of Uclés. His death, on his first recorded military expedition, precipitated a succession crisis that ended with the accession of his elder half-sister Urraca and her husband, Alfonso the Battler, already King of Navarre and Aragon, to the throne of Kingdom of Castile-León.

According to Pelayo of Oviedo, the Moorish princess Zaida was the mother of Alfonso's only son, but he is confused about the origins of Zaida. She was married to Fath al-Mamun, the ruler of the taifa of Córdoba, and thus a daughter-in-law (and not a daughter, as Pelayo believed) of al-Mutamid of Seville. Her husband died in March 1091 and Alfonso's relationship with her began later that year or in 1092, probably while the queen, Constance of Burgundy, who had provided no son, was seriously ill. Constance died in Autumn 1093. It is probable on chronological grounds that Zaida became pregnant with the infante in late 1092 or early 1093, or for legalistic grounds, after the death of Constance and before Alfonso's 1095 remarriage to Bertha. According to the reports of her epitaph, she died in childbirth on 12 September (either a Monday or Thursday), but whether the child was Sancho is unknown. Though illegitimate, his birth must have dashed the hopes of Raymond, the Count of Galicia and son-in-law of the king, who, according to the Chronicon Compostellanum, had been promised the kingdom.

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