Diego de Castilla Son of Peter I of Castile (1365–1440) Parents Isabel de Sandoval Peter of Castile Children María de Castilla y Salazar Isabel de Castilla y Salazar Pedro de Castilla y Salazar Siblings Constance of Castile, Duchess of Lancaster Isabella of Castile, Duchess of York Jean de Castille Sancho de Castilla María de Ayala Edward de Castilla Partners Isabel de Salazar