was the alférez, or commander of the royal military household, under King Alfonso VI of León and Castile from 1100/2 to 1107.
[1] He was the son of Álvar Díaz de Oca and a member of one of the leading families of Castile.
He does not appear in any contemporary records after 27 December 1107, but this may be simply because he had been replaced in the important post of alférez by Pedro González de Lara.
[3] The 13th-century historian Lucas of Tuy, in his Chronicon mundi, reports that "King Alfonso [VI] gravely offended the Castilian count García de Cabrera and in order to placate the same gave him his sister Elvira as a wife and pacified the whole kingdom that was in rebellion.
Another 13th-century history, De rebus Hispaniae, records that García was the guardian of the king's son and heir, Sancho Alfónsez, and died defending him at Uclés.