He became Grand Master of the order after the death of Gonzalo Ruiz Girón during the reign of Alfonso X of Castile.
Pedro Nuñez (priest) Founded on the initiative of Alfonso X of Castile, Pedro Núñez was named master of the order after the Battle of Moclín.
Pedro Núñez was named Grand Master of the Order of Santiago to save it from extinction.
Following the disastrous Spanish defeat after the Battle of Moclín, the future of the order was threatened due to the deaths of many of its members.
To this end, Alfonso X of Castile integrated the Order of Santa María de España into that of Santiago.