The Infante Juan of Spain, Count of Barcelona, was the third surviving son and designated heir of King Alfonso XIII of Spain and Victoria Eugenie of Battenberg, the monarch replaced by the Second Spanish Republic, and father of King Juan Carlos I, under whom a constitutional monarchy was restored. As King, he would have been Juan III of Spain. (In fact, some people call him Juan III, he was considered an exiled King in Lisbon, with his court and everything
Don Juan was born at the Palace of San Ildefonso in 1913. His father was forced into exile when the Second Spanish Republic was proclaimed on 14 April 1931. He was the third son of Alfonso XIII, but due to his brothers' renounciations a month before his death, his father King Alfonso XIII designated him as his heir. The eldest brother, Alfonso of Spain, Prince of Asturias, was born with haemophilia and when he married a commoner he renounced his rights to the throne. The secon son, Infante Jaime, Duke of Segovia, was deaf-mute since childhood and renounced his rights to the Spanish throne for him and his descendants, furthermore, when he married the mere daughter of a duke, he lost his rights again.
Don Juan married a Princess María Mercedes of Bourbon-Two Sicilies, born in Madrid in 1910. María was the daughter of Prince Carlos of Bourbon-Two Sicilies, Infante of Spain and grandson of King Ferdinand II of the Two Sicilies, and his second wife, Princess Louise of Orléans, daughter of Prince Philippe, Count of Paris, a pretender to the French throne. She was granted, at birth, the rank and precedence of an Infanta of Spain, although not the actual use of the title (she was, after all, technically, a Princess of Bourbon-Two Sicilies). Her family moved to Seville, when her father was made Military Captain General of the province. When the Second Spanish Republic forced them to exile, they lived in Cannes and later in Paris, when she studied art at the Louvre.
On 14 January 1935, she attended the wedding, in Rome, of Infanta Beatriz of Spain, daughter of Alfonso XIII. Here she met her distant cousin and future husband, the brother of the bride, the Infante Juan, Count of Barcelona, fourth son and designated heir of King Alfonso XIII of Spain. They married in Rome on 12 October 1935. When her husband took the royal title of Count of Barcelona in 1942, María gained the title of Countess of Barcelona.