Sancho Alfónsez

Sancho Alfónsez was the only son of King Alfonso VI of Castile and León; his mother was 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.