Prince or Princess of Asturias is the main substantive title used by the heir apparent, or heir presumptive to the Spanish Crown.
Imaginative portrait of King Henry III of Castile, by Calixto Ortega, 1848. He was the first Prince of Asturias, proclaimed in 1388.
Education of Prince John, by Salvador Martínez Cubells 1877. John was the only son of the Catholic Monarchs and heir of all their domains during his lifetime.
Cover of the first edition of the Political Constitution of the Spanish monarchy. Cádiz, 19 March 1812
Infanta Isabel of Spain was the eldest daughter of Queen Isabella II of Spain and her husband Francisco de Asís, Duke of Cádiz. She was the heiress presumptive to the Spanish throne from 1851 to 1857
Infanta Isabel in 1879
Infanta Isabel, age eight, with her family. From left to right: The Marchioness of Malpica with Alfonso, Prince of Asturias, on her lap; Francisco de Asís, Duke of Cádiz, Queen Isabella II of Spain, and their royal wet nurse holding Infanta María de la Concepción, and Infanta Isabel, 1860.
Infanta Isabel at age fourteen in 1865
Infanta Isabel and Prince Gaetan of two Sicillies, 1868