Mayor Guillén de Guzmán (1205–1262) was a member of one of the most aristocratic families in the court of King Ferdinand III of Castile. Her parents were Guillén Pérez de Guzmán and María González Girón, daughter of Gonzalo Rodríguez Girón and his first wife Sancha Rodríguez, and sister of Pedro Rodríguez de Guzmán, Castile's first adelantado and father of Alonso Pérez de Guzmán.
Landscape in La Alcarria where Mayor received several properties from King Alfonso X of Castile
Del Monte gate at the walls of the medieval city of Palazuelos
Guillén Pérez de Guzmán, a member of the House of Guzmán, one of the most aristocratic of the Kingdom of Castile, was the maternal grandfather of Queen Beatrice of Castile, Queen Consort of Portugal as the wife of King Alfonso III. His father was Pedro Rodríguez de Guzmán—killed in the Battle of Alarcos on July 18, 1195 and son of Rodrigo Muñoz de Guzmán—and Mahalda With his brothers Nuño and Theobald, he fought alongside King Alfonso VIII at the decisive Battle of Navas de Tolosa in 1212. Even though his kinsmen supported the Laras during the crisis that ensued after the death of King Alfonso VIII, Guillén, probably because of his marriage to a member of the Girón clan, supported Queen Berengaria of Castile and her son, the future king Ferdinand III.
Depiction of the Battle of Navas de Tolosa by 19th-century painter Francisco de Paula Van Halen, exhibited at the Senate building in Madrid.