Hurtado de Mendoza
He had a brother, Rodrigo de Mendoza, 1st Marquess of Montesclaros (or Montes-Claros) and a sister, Ana de Mendoza, who married Luis de La Cerda, 1st Marquess of Cogolludo. Juan Miguel Soler Salcedo in "Nobleza Española. Grandeza Inmemorial 1520" lists all of these. He also says that he had an older brother, Diego Hurtado de Mendoza y Pimentel, who died no later than 1531, and lists numerous younger siblings: Martín Hurtado de Mendoza y Pimentel, a second Rodrigo (Rodrigo Hurtado de Mendoza y Pimentel), Francisco Hurtado de Mendoza y Pimentel, Brianda Hurtado de Mendoza y Pimentel, Francisca Hurtado de Mendoza y Pimentel, Marina Hurtado de Mendoza y Pimentel, and another Brianda.