The historic Spanish nobility is based either on possession of a legal title recognised by the Ministry of Justice, or descent from the holder of such a title through the legitimate male line, or descent through the legitimate male line from an ancestor in possession nobility prior to 1837 (as proved by appropriate acts in public law over three generations).
The following historic noble corporations are in principle eligible to attend CILANE meetings as observers: Diputación Permanente y Consejo de la Grandeza de España, Military Orders of Santiago, Calatrava, Alcántara and Montesa, Reales Maestranzas de Caballería de Sevilla, de Ronda, de Granada, de Valencia y de Zaragoza, Real Cuerpo de la Nobleza de Madrid, Real Cuerpo de la Nobleza de Cataluña, and Junta de Nobles Linajes de Segovia.
A number of members of these corporations already attend meetings of CILANE, including Congresses, as observers on a regular basis, and provide for Jugendaustausch exchanges. A corresponding member of the sous-commission for nobility law is appointed by the Real Consejo de las Órdenes Militares.
The Jóvenes de la Nobleza Española (JNE) have autonomous observer status with the CILANE des Jeunes. As such they are eligible to attend International weekends and Congresses. Members of this group come from families belonging to one of the aforementioned historic noble corporations or must have proved their nobility in the male line prior to 1837 to the satisfaction of the corresponding member of the sous-commission.